Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
dnl
dnl GLIBCXX_CONDITIONAL (NAME, SHELL-TEST)
dnl
dnl Exactly like AM_CONDITIONAL, but delays evaluation of the test until the
dnl end of configure.  This lets tested variables be reassigned, and the
dnl conditional will depend on the final state of the variable.  For a simple
dnl example of why this is needed, see GLIBCXX_ENABLE_HOSTED.
dnl
m4_define([_m4_divert(glibcxx_diversion)], 8000)dnl
AC_DEFUN([GLIBCXX_CONDITIONAL], [dnl
  m4_divert_text([glibcxx_diversion],dnl
   AM_CONDITIONAL([$1],[$2])
  )dnl
])dnl
AC_DEFUN([GLIBCXX_EVALUATE_CONDITIONALS], [m4_undivert([glibcxx_diversion])])dnl


dnl
dnl Check to see what architecture and operating system we are compiling
dnl for.  Also, if architecture- or OS-specific flags are required for
dnl compilation, pick them up here.
dnl
AC_DEFUN([GLIBCXX_CHECK_HOST], [
  . $glibcxx_srcdir/configure.host
  AC_MSG_NOTICE([CPU config directory is $cpu_include_dir])
  AC_MSG_NOTICE([OS config directory is $os_include_dir])
])

dnl
dnl Initialize the rest of the library configury.  At this point we have
dnl variables like $host.
dnl
dnl Sets:
dnl  SUBDIRS
dnl Substs:
dnl  glibcxx_builddir     (absolute path)
dnl  glibcxx_srcdir       (absolute path)
dnl  toplevel_builddir    (absolute path)
dnl  toplevel_srcdir      (absolute path)
dnl  with_cross_host
dnl  with_newlib
dnl  with_target_subdir
dnl plus
dnl  - the variables in GLIBCXX_CHECK_HOST / configure.host
dnl  - default settings for all AM_CONFITIONAL test variables
dnl  - lots of tools, like CC and CXX
dnl
AC_DEFUN([GLIBCXX_CONFIGURE], [
  # Keep these sync'd with the list in Makefile.am.  The first provides an
  # expandable list at autoconf time; the second provides an expandable list
  # (i.e., shell variable) at configure time.
  m4_define([glibcxx_SUBDIRS],[include libsupc++ src src/c++98 src/c++11 src/c++17 src/filesystem doc python])
  SUBDIRS='glibcxx_SUBDIRS'

  # These need to be absolute paths, yet at the same time need to
  # canonicalize only relative paths, because then amd will not unmount
  # drives. Thus the use of PWDCMD: set it to 'pawd' or 'amq -w' if using amd.
  glibcxx_builddir=`${PWDCMD-pwd}`
  case $srcdir in
    [\\/$]* | ?:[\\/]*) glibcxx_srcdir=${srcdir} ;;
    *) glibcxx_srcdir=`cd "$srcdir" && ${PWDCMD-pwd} || echo "$srcdir"` ;;
  esac
  toplevel_builddir=${glibcxx_builddir}/..
  toplevel_srcdir=${glibcxx_srcdir}/..
  AC_SUBST(glibcxx_builddir)
  AC_SUBST(glibcxx_srcdir)
  AC_SUBST(toplevel_builddir)
  AC_SUBST(toplevel_srcdir)

  # We use these options to decide which functions to include.  They are
  # set from the top level.
  AC_ARG_WITH([target-subdir],
    AC_HELP_STRING([--with-target-subdir=SUBDIR],
		   [configuring in a subdirectory]))

  AC_ARG_WITH([cross-host],
    AC_HELP_STRING([--with-cross-host=HOST],
		   [configuring with a cross compiler]))

  AC_ARG_WITH([newlib],
    AC_HELP_STRING([--with-newlib],
		   [assume newlib as a system C library]))

  # Will set LN_S to either 'ln -s', 'ln', or 'cp -p' (if linking isn't
  # available).  Uncomment the next line to force a particular method.
  AC_PROG_LN_S
  #LN_S='cp -p'

  AC_CHECK_TOOL(AS, as)
  AC_CHECK_TOOL(AR, ar)
  AC_CHECK_TOOL(RANLIB, ranlib, ranlib-not-found-in-path-error)

  AM_MAINTAINER_MODE

  # Set up safe default values for all subsequent AM_CONDITIONAL tests
  # which are themselves conditionally expanded.
  ## (Right now, this only matters for enable_wchar_t, but nothing prevents
  ## other macros from doing the same.  This should be automated.)  -pme

  # Check for C library flavor since GNU/Linux platforms use different
  # configuration directories depending on the C library in use.
  AC_EGREP_CPP([_using_uclibc], [
  #include <stdio.h>
  #if __UCLIBC__
    _using_uclibc
  #endif
  ], uclibc=yes, uclibc=no)

  AC_EGREP_CPP([_using_bionic], [
  #include <stdio.h>
  #if __BIONIC__
    _using_bionic
  #endif
  ], bionic=yes, bionic=no)

  # Find platform-specific directories containing configuration info.
  # Also possibly modify flags used elsewhere, as needed by the platform.
  GLIBCXX_CHECK_HOST
])


dnl
dnl Tests for newer compiler features, or features that are present in newer
dnl compiler versions but not older compiler versions still in use, should
dnl be placed here.
dnl
dnl Defines:
dnl  WERROR='-Werror' if requested and possible; g++'s that lack the
dnl   new inlining code or the new system_header pragma will die on -Werror.
dnl   Leave it out by default and use maint-mode to use it.
dnl  SECTION_FLAGS='-ffunction-sections -fdata-sections' if
dnl   compiler supports it and the user has not requested debug mode.
dnl
AC_DEFUN([GLIBCXX_CHECK_COMPILER_FEATURES], [
  # All these tests are for C++; save the language and the compiler flags.
  # The CXXFLAGS thing is suspicious, but based on similar bits previously
  # found in GLIBCXX_CONFIGURE.
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_test_CXXFLAGS="${CXXFLAGS+set}"
  ac_save_CXXFLAGS="$CXXFLAGS"

  # Check for -ffunction-sections -fdata-sections
  AC_MSG_CHECKING([for g++ that supports -ffunction-sections -fdata-sections])
  CXXFLAGS='-g -Werror -ffunction-sections -fdata-sections'
  AC_TRY_COMPILE([int foo; void bar() { };],, [ac_fdsections=yes], [ac_fdsections=no])
  if test "$ac_test_CXXFLAGS" = set; then
    CXXFLAGS="$ac_save_CXXFLAGS"
  else
    # this is the suspicious part
    CXXFLAGS=''
  fi
  if test x"$ac_fdsections" = x"yes"; then
    SECTION_FLAGS='-ffunction-sections -fdata-sections'
  fi
  AC_MSG_RESULT($ac_fdsections)

  AC_LANG_RESTORE
  AC_SUBST(SECTION_FLAGS)
])


dnl
dnl If GNU ld is in use, check to see if tricky linker opts can be used.  If
dnl the native linker is in use, all variables will be defined to something
dnl safe (like an empty string).
dnl
dnl Defines:
dnl  SECTION_LDFLAGS='-Wl,--gc-sections' if possible
dnl  OPT_LDFLAGS='-Wl,-O1' and '-z,relro' if possible
dnl  LD (as a side effect of testing)
dnl Sets:
dnl  with_gnu_ld
dnl  glibcxx_ld_is_gold (set to "no" or "yes")
dnl  glibcxx_gnu_ld_version (possibly)
dnl
dnl The last will be a single integer, e.g., version 1.23.45.0.67.89 will
dnl set glibcxx_gnu_ld_version to 12345.  Zeros cause problems.
dnl
AC_DEFUN([GLIBCXX_CHECK_LINKER_FEATURES], [
  # If we're not using GNU ld, then there's no point in even trying these
  # tests.  Check for that first.  We should have already tested for gld
  # by now (in libtool), but require it now just to be safe...
  test -z "$SECTION_LDFLAGS" && SECTION_LDFLAGS=''
  test -z "$OPT_LDFLAGS" && OPT_LDFLAGS=''
  AC_REQUIRE([AC_PROG_LD])
  AC_REQUIRE([AC_PROG_AWK])

  # The name set by libtool depends on the version of libtool.  Shame on us
  # for depending on an impl detail, but c'est la vie.  Older versions used
  # ac_cv_prog_gnu_ld, but now it's lt_cv_prog_gnu_ld, and is copied back on
  # top of with_gnu_ld (which is also set by --with-gnu-ld, so that actually
  # makes sense).  We'll test with_gnu_ld everywhere else, so if that isn't
  # set (hence we're using an older libtool), then set it.
  if test x${with_gnu_ld+set} != xset; then
    if test x${ac_cv_prog_gnu_ld+set} != xset; then
      # We got through "ac_require(ac_prog_ld)" and still not set?  Huh?
      with_gnu_ld=no
    else
      with_gnu_ld=$ac_cv_prog_gnu_ld
    fi
  fi

  # Start by getting the version number.  I think the libtool test already
  # does some of this, but throws away the result.
  glibcxx_ld_is_gold=no
  if test x"$with_gnu_ld" = x"yes"; then
    AC_MSG_CHECKING([for ld version])
    changequote(,)
    if $LD --version 2>/dev/null | grep 'GNU gold' >/dev/null 2>&1; then
      glibcxx_ld_is_gold=yes
    fi
    ldver=`$LD --version 2>/dev/null |
	   sed -e 's/[. ][0-9]\{8\}$//;s/.* \([^ ]\{1,\}\)$/\1/; q'`
    changequote([,])
    glibcxx_gnu_ld_version=`echo $ldver | \
	   $AWK -F. '{ if (NF<3) [$]3=0; print ([$]1*100+[$]2)*100+[$]3 }'`
    AC_MSG_RESULT($glibcxx_gnu_ld_version)
  fi

  # Set --gc-sections.
  glibcxx_have_gc_sections=no
  if test "$glibcxx_ld_is_gold" = "yes"; then
    if $LD --help 2>/dev/null | grep gc-sections >/dev/null 2>&1; then
      glibcxx_have_gc_sections=yes
    fi
  else
    glibcxx_gcsections_min_ld=21602
    if test x"$with_gnu_ld" = x"yes" &&
	test $glibcxx_gnu_ld_version -gt $glibcxx_gcsections_min_ld ; then
      glibcxx_have_gc_sections=yes
    fi
  fi
  if test "$glibcxx_have_gc_sections" = "yes"; then
    # Sufficiently young GNU ld it is!  Joy and bunny rabbits!
    # NB: This flag only works reliably after 2.16.1. Configure tests
    # for this are difficult, so hard wire a value that should work.

    ac_test_CFLAGS="${CFLAGS+set}"
    ac_save_CFLAGS="$CFLAGS"
    CFLAGS='-Wl,--gc-sections'

    # Check for -Wl,--gc-sections
    AC_MSG_CHECKING([for ld that supports -Wl,--gc-sections])
    AC_TRY_LINK([ int one(void) { return 1; }
     int two(void) { return 2; }
	], [ two(); ] , [ac_gcsections=yes], [ac_gcsections=no])
    if test "$ac_gcsections" = "yes"; then
      rm -f conftest.c
      touch conftest.c
      if $CC -c conftest.c; then
	if $LD --gc-sections -o conftest conftest.o 2>&1 | \
	   grep "Warning: gc-sections option ignored" > /dev/null; then
	  ac_gcsections=no
	fi
      fi
      rm -f conftest.c conftest.o conftest
    fi
    if test "$ac_gcsections" = "yes"; then
      SECTION_LDFLAGS="-Wl,--gc-sections $SECTION_LDFLAGS"
    fi
    AC_MSG_RESULT($ac_gcsections)

    if test "$ac_test_CFLAGS" = set; then
      CFLAGS="$ac_save_CFLAGS"
    else
      # this is the suspicious part
      CFLAGS=''
    fi
  fi

  # Set -z,relro.
  # Note this is only for shared objects.
  ac_ld_relro=no
  if test x"$with_gnu_ld" = x"yes"; then
    AC_MSG_CHECKING([for ld that supports -Wl,-z,relro])
    cxx_z_relo=`$LD -v --help 2>/dev/null | grep "z relro"`
    if test -n "$cxx_z_relo"; then
      OPT_LDFLAGS="-Wl,-z,relro"
      ac_ld_relro=yes
    fi
    AC_MSG_RESULT($ac_ld_relro)
  fi

  # Set linker optimization flags.
  if test x"$with_gnu_ld" = x"yes"; then
    OPT_LDFLAGS="-Wl,-O1 $OPT_LDFLAGS"
  fi

  AC_SUBST(SECTION_LDFLAGS)
  AC_SUBST(OPT_LDFLAGS)
])


dnl
dnl Check for headers for, and arguments to, the setrlimit() function.
dnl Used only in testsuite_hooks.h.  Called from GLIBCXX_CONFIGURE_TESTSUITE.
dnl
dnl Defines:
dnl  _GLIBCXX_RES_LIMITS if we can set artificial resource limits
dnl  various HAVE_LIMIT_* for individual limit names
dnl
AC_DEFUN([GLIBCXX_CHECK_SETRLIMIT_ancilliary], [
  AC_MSG_CHECKING([for RLIMIT_$1])
  AC_TRY_COMPILE(
    [#include <unistd.h>
     #include <sys/time.h>
     #include <sys/resource.h>
    ],
    [ int f = RLIMIT_$1 ; ],
    [glibcxx_mresult=1], [glibcxx_mresult=0])
  AC_DEFINE_UNQUOTED(HAVE_LIMIT_$1, $glibcxx_mresult,
		     [Only used in build directory testsuite_hooks.h.])
  if test $glibcxx_mresult = 1 ; then res=yes ; else res=no ; fi
  AC_MSG_RESULT($res)
])

AC_DEFUN([GLIBCXX_CHECK_SETRLIMIT], [
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  setrlimit_have_headers=yes
  AC_CHECK_HEADERS(unistd.h sys/time.h sys/resource.h,
		   [],
		   [setrlimit_have_headers=no])
  # If don't have the headers, then we can't run the tests now, and we
  # won't be seeing any of these during testsuite compilation.
  if test $setrlimit_have_headers = yes; then
    # Can't do these in a loop, else the resulting syntax is wrong.
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(DATA)
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(RSS)
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(VMEM)
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(AS)
    GLIBCXX_CHECK_SETRLIMIT_ancilliary(FSIZE)

    # Check for rlimit, setrlimit.
    AC_CACHE_VAL(glibcxx_cv_setrlimit, [
      AC_TRY_COMPILE(
	[#include <unistd.h>
	 #include <sys/time.h>
	 #include <sys/resource.h>
	],
	[struct rlimit r;
	 setrlimit(0, &r);],
	[glibcxx_cv_setrlimit=yes], [glibcxx_cv_setrlimit=no])
    ])
  fi

  AC_MSG_CHECKING([for testsuite resource limits support])
  if test $setrlimit_have_headers = yes && test $glibcxx_cv_setrlimit = yes; then
    ac_res_limits=yes
    AC_DEFINE(_GLIBCXX_RES_LIMITS, 1,
	      [Define if using setrlimit to set resource limits during
	      "make check"])
  else
    ac_res_limits=no
  fi
  AC_LANG_RESTORE
  AC_MSG_RESULT($ac_res_limits)
])


dnl
dnl Check whether S_ISREG (Posix) or S_IFREG is available in <sys/stat.h>.
dnl Define HAVE_S_ISREG / HAVE_S_IFREG appropriately.
dnl
AC_DEFUN([GLIBCXX_CHECK_S_ISREG_OR_S_IFREG], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  AC_MSG_CHECKING([for S_ISREG or S_IFREG])
  AC_CACHE_VAL(glibcxx_cv_S_ISREG, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <sys/stat.h>],
      [struct stat buffer;
       fstat(0, &buffer);
       S_ISREG(buffer.st_mode);],
      [glibcxx_cv_S_ISREG=yes],
      [glibcxx_cv_S_ISREG=no])
  ])
  AC_CACHE_VAL(glibcxx_cv_S_IFREG, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <sys/stat.h>],
      [struct stat buffer;
       fstat(0, &buffer);
       S_IFREG & buffer.st_mode;],
      [glibcxx_cv_S_IFREG=yes],
      [glibcxx_cv_S_IFREG=no])
  ])
  res=no
  if test $glibcxx_cv_S_ISREG = yes; then
    AC_DEFINE(HAVE_S_ISREG, 1,
	      [Define if S_ISREG is available in <sys/stat.h>.])
    res=S_ISREG
  elif test $glibcxx_cv_S_IFREG = yes; then
    AC_DEFINE(HAVE_S_IFREG, 1,
	      [Define if S_IFREG is available in <sys/stat.h>.])
    res=S_IFREG
  fi
  AC_MSG_RESULT($res)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])


dnl
dnl Check whether poll is available in <poll.h>, and define HAVE_POLL.
dnl
AC_DEFUN([GLIBCXX_CHECK_POLL], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  AC_MSG_CHECKING([for poll])
  AC_CACHE_VAL(glibcxx_cv_POLL, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <poll.h>],
      [struct pollfd pfd[1];
       pfd[0].events = POLLIN;
       poll(pfd, 1, 0);],
      [glibcxx_cv_POLL=yes],
      [glibcxx_cv_POLL=no])
  ])
  if test $glibcxx_cv_POLL = yes; then
    AC_DEFINE(HAVE_POLL, 1, [Define if poll is available in <poll.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_POLL)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])


dnl
dnl Check whether writev is available in <sys/uio.h>, and define HAVE_WRITEV.
dnl
AC_DEFUN([GLIBCXX_CHECK_WRITEV], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  AC_MSG_CHECKING([for writev])
  AC_CACHE_VAL(glibcxx_cv_WRITEV, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <sys/uio.h>],
      [struct iovec iov[2];
       writev(0, iov, 0);],
      [glibcxx_cv_WRITEV=yes],
      [glibcxx_cv_WRITEV=no])
  ])
  if test $glibcxx_cv_WRITEV = yes; then
    AC_DEFINE(HAVE_WRITEV, 1, [Define if writev is available in <sys/uio.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_WRITEV)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])


dnl
dnl Check whether int64_t is available in <stdint.h>, and define HAVE_INT64_T.
dnl Also check whether int64_t is actually a typedef to long or long long.
dnl
AC_DEFUN([GLIBCXX_CHECK_INT64_T], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS

  AC_MSG_CHECKING([for int64_t])
  AC_CACHE_VAL(glibcxx_cv_INT64_T, [
    AC_TRY_COMPILE(
      [#include <stdint.h>],
      [int64_t var;],
      [glibcxx_cv_INT64_T=yes],
      [glibcxx_cv_INT64_T=no])
  ])

  if test $glibcxx_cv_INT64_T = yes; then
    AC_DEFINE(HAVE_INT64_T, 1, [Define if int64_t is available in <stdint.h>.])
    AC_MSG_RESULT($glibcxx_cv_INT64_T)

    AC_MSG_CHECKING([for int64_t as long])
    AC_CACHE_VAL(glibcxx_cv_int64_t_long, [
      AC_TRY_COMPILE(
	[#include <stdint.h>
	template<typename, typename> struct same { enum { value = -1 }; };
	template<typename Tp> struct same<Tp, Tp> { enum { value = 1 }; };
	int array[same<int64_t, long>::value];], [],
	[glibcxx_cv_int64_t_long=yes], [glibcxx_cv_int64_t_long=no])
    ])

    if test $glibcxx_cv_int64_t_long = yes; then
      AC_DEFINE(HAVE_INT64_T_LONG, 1, [Define if int64_t is a long.])
      AC_MSG_RESULT($glibcxx_cv_int64_t_long)
    fi

    AC_MSG_CHECKING([for int64_t as long long])
    AC_CACHE_VAL(glibcxx_cv_int64_t_long_long, [
      AC_TRY_COMPILE(
	[#include <stdint.h>
	template<typename, typename> struct same { enum { value = -1 }; };
	template<typename Tp> struct same<Tp, Tp> { enum { value = 1 }; };
	int array[same<int64_t, long long>::value];], [],
	[glibcxx_cv_int64_t_long_long=yes], [glibcxx_cv_int64_t_long_long=no])
    ])

    if test $glibcxx_cv_int64_t_long_long = yes; then
      AC_DEFINE(HAVE_INT64_T_LONG_LONG, 1, [Define if int64_t is a long long.])
      AC_MSG_RESULT($glibcxx_cv_int64_t_long_long)
    fi
  fi

  AC_LANG_RESTORE
])


dnl
dnl Check whether LFS support is available.
dnl
AC_DEFUN([GLIBCXX_CHECK_LFS], [
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"
  AC_MSG_CHECKING([for LFS support])
  AC_CACHE_VAL(glibcxx_cv_LFS, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <unistd.h>
       #include <stdio.h>
       #include <sys/stat.h>
      ],
      [FILE* fp;
       fopen64("t", "w");
       fseeko64(fp, 0, SEEK_CUR);
       ftello64(fp);
       lseek64(1, 0, SEEK_CUR);
       struct stat64 buf;
       fstat64(1, &buf);],
      [glibcxx_cv_LFS=yes],
      [glibcxx_cv_LFS=no])
  ])
  if test $glibcxx_cv_LFS = yes; then
    AC_DEFINE(_GLIBCXX_USE_LFS, 1, [Define if LFS support is available.])
  fi
  AC_MSG_RESULT($glibcxx_cv_LFS)
  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])


dnl
dnl Check for whether a fully dynamic basic_string implementation should
dnl be turned on, that does not put empty objects in per-process static
dnl memory (mostly useful together with shared memory allocators, see PR
dnl libstdc++/16612 for details).
dnl
dnl --enable-fully-dynamic-string defines _GLIBCXX_FULLY_DYNAMIC_STRING to 1
dnl --disable-fully-dynamic-string defines _GLIBCXX_FULLY_DYNAMIC_STRING to 0
dnl otherwise undefined
dnl  +  Usage:  GLIBCXX_ENABLE_FULLY_DYNAMIC_STRING[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_FULLY_DYNAMIC_STRING], [
  GLIBCXX_ENABLE(fully-dynamic-string,$1,,[do not put empty strings in per-process static memory])
  if test $enable_fully_dynamic_string = yes; then
    enable_fully_dynamic_string_def=1
  else
    enable_fully_dynamic_string_def=0
  fi
  AC_DEFINE_UNQUOTED([_GLIBCXX_FULLY_DYNAMIC_STRING], [${enable_fully_dynamic_string_def}],
	      [Define to 1 if a fully dynamic basic_string is wanted, 0 to disable, undefined for platform defaults])
])


dnl
dnl Does any necessary configuration of the testsuite directory.  Generates
dnl the testsuite_hooks.h header.
dnl
dnl GLIBCXX_ENABLE_SYMVERS and GLIBCXX_IS_NATIVE must be done before this.
dnl
dnl Sets:
dnl  enable_abi_check
dnl  GLIBCXX_TEST_WCHAR_T
dnl  GLIBCXX_TEST_THREAD
dnl Substs:
dnl  baseline_dir
dnl  baseline_subdir_switch
dnl
AC_DEFUN([GLIBCXX_CONFIGURE_TESTSUITE], [
  # Do checks for resource limit functions.
  GLIBCXX_CHECK_SETRLIMIT

  if $GLIBCXX_IS_NATIVE ; then
    # Look for setenv, so that extended locale tests can be performed.
    GLIBCXX_CHECK_STDLIB_DECL_AND_LINKAGE_3(setenv)
  fi

  if $GLIBCXX_IS_NATIVE && test $is_hosted = yes &&
     test $enable_symvers != no; then
    case "$host" in
      *-*-cygwin*)
	enable_abi_check=no ;;
      *)
	enable_abi_check=yes ;;
    esac
  else
    # Only build this as native, since automake does not understand
    # CXX_FOR_BUILD.
    enable_abi_check=no
  fi

  # Export file names for ABI checking.
  baseline_dir="$glibcxx_srcdir/config/abi/post/${abi_baseline_pair}"
  AC_SUBST(baseline_dir)
  baseline_subdir_switch="$abi_baseline_subdir_switch"
  AC_SUBST(baseline_subdir_switch)
])


dnl
dnl Does any necessary configuration for docbook in the docs directory.
dnl
dnl XSLTPROC must be set before this
dnl
dnl Sets:
dnl  glibcxx_stylesheets
dnl Substs:
dnl  XSL_STYLE_DIR
dnl
AC_DEFUN([GLIBCXX_CONFIGURE_DOCBOOK], [

glibcxx_docbook_url=http://docbook.sourceforge.net/release/xsl-ns/current/

AC_MSG_CHECKING([for local stylesheet directory])
glibcxx_local_stylesheets=no
if test x${XMLCATALOG} = xyes && xsl_style_dir=`xmlcatalog "" $glibcxx_docbook_url 2>/dev/null`
then
  XSL_STYLE_DIR=`echo $xsl_style_dir | sed -n 's;^file://;;p'`
  glibcxx_local_stylesheets=yes
else
  for dir in \
    /usr/share/sgml/docbook/xsl-ns-stylesheets \
    /usr/share/xml/docbook/stylesheet/docbook-xsl-ns \
    /usr/share/xml/docbook/stylesheet/nwalsh5/current \
    /usr/share/xml/docbook/stylesheet/nwalsh/current
  do
    if test -d $dir; then
      glibcxx_local_stylesheets=yes
      XSL_STYLE_DIR=$dir
      break
    fi
  done
fi
AC_MSG_RESULT($glibcxx_local_stylesheets)

if test x"$glibcxx_local_stylesheets" = x"yes"; then
  AC_SUBST(XSL_STYLE_DIR)
  AC_MSG_NOTICE($XSL_STYLE_DIR)

  AC_MSG_CHECKING([for docbook stylesheets for documentation creation])
  glibcxx_stylesheets=no
  if test x${XMLCATALOG} = xno || xmlcatalog "" $glibcxx_docbook_url/xhtml/docbook.xsl >/dev/null 2>&1; then
    if test x${XSLTPROC} = xyes && echo '<title/>' | xsltproc --noout --nonet --xinclude $glibcxx_docbook_url/xhtml/docbook.xsl - 2>/dev/null; then
      glibcxx_stylesheets=yes
    fi
  fi
  AC_MSG_RESULT($glibcxx_stylesheets)

else
  glibcxx_stylesheets=no
fi

# Check for epub3 dependencies.
AC_MSG_CHECKING([for epub3 stylesheets for documentation creation])
glibcxx_epub_stylesheets=no
if test x"$glibcxx_local_stylesheets" = x"yes"; then
   if test -f "$XSL_STYLE_DIR/epub3/chunk.xsl"; then
      glibcxx_epub_stylesheets=yes
   fi
fi
AC_MSG_RESULT($glibcxx_epub_stylesheets)
AM_CONDITIONAL(BUILD_EPUB, test x"$glibcxx_epub_stylesheets" = x"yes")

])


dnl
dnl Set up *_INCLUDES variables for all sundry Makefile.am's.
dnl
dnl Substs:
dnl  GLIBCXX_INCLUDES
dnl  TOPLEVEL_INCLUDES
dnl
AC_DEFUN([GLIBCXX_EXPORT_INCLUDES], [
  # Used for every C++ compile we perform.
  GLIBCXX_INCLUDES="\
-I$glibcxx_builddir/include/$host_alias \
-I$glibcxx_builddir/include \
-I$glibcxx_srcdir/libsupc++"

  # For Canadian crosses, pick this up too.
  if test $CANADIAN = yes; then
    GLIBCXX_INCLUDES="$GLIBCXX_INCLUDES -I\${includedir}"
  fi

  # Stuff in the actual top level.  Currently only used by libsupc++ to
  # get unwind* headers from the libgcc dir.
  #TOPLEVEL_INCLUDES='-I$(toplevel_srcdir)/libgcc -I$(toplevel_srcdir)/include'
  TOPLEVEL_INCLUDES='-I$(toplevel_srcdir)/libgcc'

  # Now, export this to all the little Makefiles....
  AC_SUBST(GLIBCXX_INCLUDES)
  AC_SUBST(TOPLEVEL_INCLUDES)
])


dnl
dnl Set up *_FLAGS and *FLAGS variables for all sundry Makefile.am's.
dnl (SECTION_FLAGS is done under CHECK_COMPILER_FEATURES.)
dnl
dnl Substs:
dnl  OPTIMIZE_CXXFLAGS
dnl  WARN_FLAGS
dnl
AC_DEFUN([GLIBCXX_EXPORT_FLAGS], [
  # Optimization flags that are probably a good idea for thrill-seekers. Just
  # uncomment the lines below and make, everything else is ready to go...
  # Alternatively OPTIMIZE_CXXFLAGS can be set in configure.host.
  # OPTIMIZE_CXXFLAGS = -O3 -fstrict-aliasing -fvtable-gc
  AC_SUBST(OPTIMIZE_CXXFLAGS)

  WARN_FLAGS="-Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi=2"
  AC_SUBST(WARN_FLAGS)
])


dnl
dnl All installation directory information is determined here.
dnl
dnl Substs:
dnl  gxx_install_dir
dnl  glibcxx_prefixdir
dnl  glibcxx_toolexecdir
dnl  glibcxx_toolexeclibdir
dnl
dnl Assumes cross_compiling bits already done, and with_cross_host in
dnl particular.
dnl
dnl This logic must match gcc/configure.ac's setting of gcc_gxx_include_dir.
dnl config/gxx-include-dir.m4 must be kept consistant with this as well.
AC_DEFUN([GLIBCXX_EXPORT_INSTALL_INFO], [
  glibcxx_toolexecdir=no
  glibcxx_toolexeclibdir=no
  glibcxx_prefixdir=$prefix

  AC_MSG_CHECKING([for gxx-include-dir])
  AC_ARG_WITH([gxx-include-dir],
    AC_HELP_STRING([--with-gxx-include-dir=DIR],
		   [installation directory for include files]),
    [case "$withval" in
      yes) AC_MSG_ERROR([Missing directory for --with-gxx-include-dir]) ;;
      no)  gxx_include_dir=no ;;
      *)   gxx_include_dir=$withval ;;
     esac],
    [gxx_include_dir=no])
  AC_MSG_RESULT($gxx_include_dir)

  AC_MSG_CHECKING([for --enable-version-specific-runtime-libs])
  AC_ARG_ENABLE([version-specific-runtime-libs],
    AC_HELP_STRING([--enable-version-specific-runtime-libs],
		   [Specify that runtime libraries should be installed in a compiler-specific directory]),
    [case "$enableval" in
      yes) version_specific_libs=yes ;;
      no)  version_specific_libs=no ;;
      *)   AC_MSG_ERROR([Unknown argument to enable/disable version-specific libs]);;
     esac],
    [version_specific_libs=no])
  AC_MSG_RESULT($version_specific_libs)

  GCC_WITH_TOOLEXECLIBDIR

  # Default case for install directory for include files.
  if test $version_specific_libs = no && test $gxx_include_dir = no; then
    gxx_include_dir='include/c++/${gcc_version}'
    if test -n "$with_cross_host" &&
       test x"$with_cross_host" != x"no"; then
      gxx_include_dir='${prefix}/${target_alias}/'"$gxx_include_dir"
    else
      gxx_include_dir='${prefix}/'"$gxx_include_dir"
    fi
  fi

  # Version-specific runtime libs processing.
  if test $version_specific_libs = yes; then
    # Need the gcc compiler version to know where to install libraries
    # and header files if --enable-version-specific-runtime-libs option
    # is selected.  FIXME: these variables are misnamed, there are
    # no executables installed in _toolexecdir or _toolexeclibdir.
    if test x"$gxx_include_dir" = x"no"; then
      gxx_include_dir='${libdir}/gcc/${host_alias}/${gcc_version}/include/c++'
    fi
    glibcxx_toolexecdir='${libdir}/gcc/${host_alias}'
    glibcxx_toolexeclibdir='${toolexecdir}/${gcc_version}$(MULTISUBDIR)'
  fi

  # Calculate glibcxx_toolexecdir, glibcxx_toolexeclibdir
  # Install a library built with a cross compiler in tooldir, not libdir.
  if test x"$glibcxx_toolexecdir" = x"no"; then
    if test -n "$with_cross_host" &&
       test x"$with_cross_host" != x"no"; then
      glibcxx_toolexecdir='${exec_prefix}/${host_alias}'
      case ${with_toolexeclibdir} in
	no)
	  glibcxx_toolexeclibdir='${toolexecdir}/lib'
	  ;;
	*)
	  glibcxx_toolexeclibdir=${with_toolexeclibdir}
	  ;;
      esac
    else
      glibcxx_toolexecdir='${libdir}/gcc/${host_alias}'
      glibcxx_toolexeclibdir='${libdir}'
    fi
    multi_os_directory=`$CXX -print-multi-os-directory`
    case $multi_os_directory in
      .) ;; # Avoid trailing /.
      *) glibcxx_toolexeclibdir=$glibcxx_toolexeclibdir/$multi_os_directory ;;
    esac
  fi

  AC_MSG_CHECKING([for install location])
  AC_MSG_RESULT($gxx_include_dir)

  AC_SUBST(glibcxx_prefixdir)
  AC_SUBST(gxx_include_dir)
  AC_SUBST(glibcxx_toolexecdir)
  AC_SUBST(glibcxx_toolexeclibdir)
])


dnl
dnl GLIBCXX_ENABLE
dnl    (FEATURE, DEFAULT, HELP-ARG, HELP-STRING)
dnl    (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, permit a|b|c)
dnl    (FEATURE, DEFAULT, HELP-ARG, HELP-STRING, SHELL-CODE-HANDLER)
dnl
dnl See manual/appendix_porting.html#appendix.porting.build_hacking for
dnl documentation.
dnl
m4_define([GLIBCXX_ENABLE],[dnl
m4_define([_g_switch],[--enable-$1])dnl
m4_define([_g_help],[AC_HELP_STRING([_g_switch$3],[$4 @<:@default=$2@:>@])])dnl
 AC_ARG_ENABLE([$1],m4_dquote(_g_help),
  m4_bmatch([$5],
   [^permit ],
     [[
      case "$enableval" in
       m4_bpatsubst([$5],[permit ])) ;;
       *) AC_MSG_ERROR(Unknown argument to enable/disable $1) ;;
	  dnl Idea for future:  generate a URL pointing to
	  dnl "onlinedocs/configopts.html#whatever"
      esac
     ]],
   [^$],
     [[
      case "$enableval" in
       yes|no) ;;
       *) AC_MSG_ERROR(Argument to enable/disable $1 must be yes or no) ;;
      esac
     ]],
   [[$5]]),
  [enable_]m4_bpatsubst([$1],-,_)[=][$2])
m4_undefine([_g_switch])dnl
m4_undefine([_g_help])dnl
])


dnl
dnl Check for ISO/IEC 9899:1999 "C99" support.
dnl
dnl --enable-c99 defines _GLIBCXX_USE_C99
dnl --disable-c99 leaves _GLIBCXX_USE_C99 undefined
dnl  +  Usage:  GLIBCXX_ENABLE_C99[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl  +  If 'C99' stuff is not available, ignores DEFAULT and sets `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_C99], [
  GLIBCXX_ENABLE(c99,$1,,[turns on ISO/IEC 9899:1999 support])

  if test x"$enable_c99" = x"yes"; then
    AC_LANG_SAVE
    AC_LANG_CPLUSPLUS

    # Use -std=c++98 (instead of -std=gnu++98) because leaving __STRICT_ANSI__
    # undefined may cause fake C99 facilities, like pre-standard snprintf,
    # to be spuriously enabled.
    ac_save_CXXFLAGS="$CXXFLAGS"
    CXXFLAGS="$CXXFLAGS -std=c++98"
    ac_save_LIBS="$LIBS"
    ac_save_gcc_no_link="$gcc_no_link"

    if test x$gcc_no_link != xyes; then
      # Use -fno-exceptions to that the C driver can link these tests without
      # hitting undefined references to personality routines.
      CXXFLAGS="$CXXFLAGS -fno-exceptions"
      AC_CHECK_LIB(m, sin, [LIBS="$LIBS -lm"], [
        # Use the default compile-only tests in GCC_TRY_COMPILE_OR_LINK
        gcc_no_link=yes
      ])
    fi

    # Check for the existence of <math.h> functions used if C99 is enabled.
    AC_MSG_CHECKING([for ISO C99 support in <math.h> for C++98])
    AC_CACHE_VAL(glibcxx_cv_c99_math_cxx98, [
      GCC_TRY_COMPILE_OR_LINK(
        [#include <math.h>
         volatile double d1, d2;
         volatile int i;],
        [i = fpclassify(d1);
         i = isfinite(d1);
         i = isinf(d1);
         i = isnan(d1);
         i = isnormal(d1);
         i = signbit(d1);
         i = isgreater(d1, d2);
         i = isgreaterequal(d1, d2);
         i = isless(d1, d2);
         i = islessequal(d1, d2);
         i = islessgreater(d1, d2);
         i = islessgreater(d1, d2);
         i = isunordered(d1, d2);
        ], [glibcxx_cv_c99_math_cxx98=yes], [glibcxx_cv_c99_math_cxx98=no])
    ])
    AC_MSG_RESULT($glibcxx_cv_c99_math_cxx98)
    if test x"$glibcxx_cv_c99_math_cxx98" = x"yes"; then
      AC_DEFINE(_GLIBCXX98_USE_C99_MATH, 1,
        [Define if C99 functions or macros in <math.h> should be imported
        in <cmath> in namespace std for C++98.])
    fi

    # Check for the existence of <complex.h> complex math functions.
    # This is necessary even though libstdc++ uses the builtin versions
    # of these functions, because if the builtin cannot be used, a reference
    # to the library function is emitted.
    AC_CHECK_HEADERS(tgmath.h, ac_has_tgmath_h=yes, ac_has_tgmath_h=no)
    AC_CHECK_HEADERS(complex.h, ac_has_complex_h=yes, ac_has_complex_h=no)
    if test x"$ac_has_complex_h" = x"yes"; then
      AC_MSG_CHECKING([for ISO C99 support in <complex.h> for C++98])
      AC_CACHE_VAL(glibcxx_cv_c99_complex_cxx98, [
        GCC_TRY_COMPILE_OR_LINK(
          [#include <complex.h>
           typedef __complex__ float float_type;
           typedef __complex__ double double_type;
           typedef __complex__ long double ld_type;
           volatile float_type tmpf;
           volatile double_type tmpd;
           volatile ld_type tmpld;
           volatile float f;
           volatile double d;
           volatile long double ld;],
          [f = cabsf(tmpf);
           f = cargf(tmpf);
           tmpf = ccosf(tmpf);
           tmpf = ccoshf(tmpf);
           tmpf = cexpf(tmpf);
           tmpf = clogf(tmpf);
           tmpf = csinf(tmpf);
           tmpf = csinhf(tmpf);
           tmpf = csqrtf(tmpf);
           tmpf = ctanf(tmpf);
           tmpf = ctanhf(tmpf);
           tmpf = cpowf(tmpf, tmpf);
           tmpf = cprojf(tmpf);
           d = cabs(tmpd);
           d = carg(tmpd);
           tmpd = ccos(tmpd);
           tmpd = ccosh(tmpd);
           tmpd = cexp(tmpd);
           tmpd = clog(tmpd);
           tmpd = csin(tmpd);
           tmpd = csinh(tmpd);
           tmpd = csqrt(tmpd);
           tmpd = ctan(tmpd);
           tmpd = ctanh(tmpd);
           tmpd = cpow(tmpd, tmpd);
           tmpd = cproj(tmpd);
           ld = cabsl(tmpld);
           ld = cargl(tmpld);
           tmpld = ccosl(tmpld);
           tmpld = ccoshl(tmpld);
           tmpld = cexpl(tmpld);
           tmpld = clogl(tmpld);
           tmpld = csinl(tmpld);
           tmpld = csinhl(tmpld);
           tmpld = csqrtl(tmpld);
           tmpld = ctanl(tmpld);
           tmpld = ctanhl(tmpld);
           tmpld = cpowl(tmpld, tmpld);
           tmpld = cprojl(tmpld);
          ], [glibcxx_cv_c99_complex_cxx98=yes], [glibcxx_cv_c99_complex_cxx98=no])
      ])
    fi
    AC_MSG_RESULT($glibcxx_cv_c99_complex_cxx98)
    if test x"$glibcxx_cv_c99_complex_cxx98" = x"yes"; then
      AC_DEFINE(_GLIBCXX98_USE_C99_COMPLEX, 1,
        [Define if C99 functions in <complex.h> should be used in
        <complex> for C++98. Using compiler builtins for these functions
        requires corresponding C99 library functions to be present.])
    fi

    # Check for the existence in <stdio.h> of vscanf, et. al.
    AC_MSG_CHECKING([for ISO C99 support in <stdio.h> for C++98])
    AC_CACHE_VAL(glibcxx_cv_c99_stdio_cxx98, [
      GCC_TRY_COMPILE_OR_LINK(
        [#include <stdio.h>
         #include <stdarg.h>
         void foo(char* fmt, ...)
         {
           va_list args; va_start(args, fmt);
           vfscanf(stderr, "%i", args);
           vscanf("%i", args);
           vsnprintf(fmt, 0, "%i", args);
           vsscanf(fmt, "%i", args);
           snprintf(fmt, 0, "%i");
         }], [],
        [glibcxx_cv_c99_stdio_cxx98=yes], [glibcxx_cv_c99_stdio_cxx98=no])
    ])
    AC_MSG_RESULT($glibcxx_cv_c99_stdio_cxx98)
    if test x"$glibcxx_cv_c99_stdio_cxx98" = x"yes"; then
      AC_DEFINE(_GLIBCXX98_USE_C99_STDIO, 1,
        [Define if C99 functions or macros in <stdio.h> should be imported
        in <cstdio> in namespace std for C++98.])
    fi

    # Check for the existence in <stdlib.h> of lldiv_t, et. al.
    AC_MSG_CHECKING([for ISO C99 support in <stdlib.h> for C++98])
    AC_CACHE_VAL(glibcxx_cv_c99_stdlib_cxx98, [
      GCC_TRY_COMPILE_OR_LINK(
        [#include <stdlib.h>
         volatile float f;
         volatile long double ld;
         volatile unsigned long long ll;
         lldiv_t mydivt;],
        [char* tmp;
         f = strtof("gnu", &tmp);
         ld = strtold("gnu", &tmp);
         ll = strtoll("gnu", &tmp, 10);
         ll = strtoull("gnu", &tmp, 10);
         ll = llabs(10);
         mydivt = lldiv(10,1);
         ll = mydivt.quot;
         ll = mydivt.rem;
         ll = atoll("10");
         _Exit(0);
        ], [glibcxx_cv_c99_stdlib_cxx98=yes], [glibcxx_cv_c99_stdlib_cxx98=no])
    ])
    AC_MSG_RESULT($glibcxx_cv_c99_stdlib_cxx98)
    if test x"$glibcxx_cv_c99_stdlib_cxx98" = x"yes"; then
      AC_DEFINE(_GLIBCXX98_USE_C99_STDLIB, 1,
        [Define if C99 functions or macros in <stdlib.h> should be imported
        in <cstdlib> in namespace std for C++98.])
    fi

    # Check for the existence in <wchar.h> of wcstold, etc.
    if test x"$ac_has_wchar_h" = xyes &&
       test x"$ac_has_wctype_h" = xyes; then
      AC_MSG_CHECKING([for ISO C99 support in <wchar.h> for C++98])
      AC_CACHE_VAL(glibcxx_cv_c99_wchar_cxx98, [
        AC_TRY_COMPILE([#include <wchar.h>
          namespace test
          {
            using ::wcstold;
            using ::wcstoll;
            using ::wcstoull;
          }
        ], [], [glibcxx_cv_c99_wchar_cxx98=yes], [glibcxx_cv_c99_wchar_cxx98=no])
      ])

      # Checks for wide character functions that may not be present.
      # Injection of these is wrapped with guard macros.
      # NB: only put functions here, instead of immediately above, if
      # absolutely necessary.
      AC_TRY_COMPILE([#include <wchar.h>
        namespace test { using ::vfwscanf; }], [],
        [AC_DEFINE(HAVE_VFWSCANF, 1, [Defined if vfwscanf exists.])], [])

      AC_TRY_COMPILE([#include <wchar.h>
        namespace test { using ::vswscanf; }], [],
        [AC_DEFINE(HAVE_VSWSCANF, 1, [Defined if vswscanf exists.])], [])

      AC_TRY_COMPILE([#include <wchar.h>
        namespace test { using ::vwscanf; }], [],
        [AC_DEFINE(HAVE_VWSCANF, 1, [Defined if vwscanf exists.])], [])

      AC_TRY_COMPILE([#include <wchar.h>
        namespace test { using ::wcstof; }], [],
        [AC_DEFINE(HAVE_WCSTOF, 1, [Defined if wcstof exists.])], [])

      AC_TRY_COMPILE([#include <wctype.h>],
        [wint_t t; int i = iswblank(t);],
        [AC_DEFINE(HAVE_ISWBLANK, 1, [Defined if iswblank exists.])], [])

      AC_MSG_RESULT($glibcxx_cv_c99_wchar_cxx98)
      if test x"$glibcxx_cv_c99_wchar_cxx98" = x"yes"; then
        AC_DEFINE(_GLIBCXX98_USE_C99_WCHAR, 1,
          [Define if C99 functions or macros in <wchar.h> should be imported
          in <cwchar> in namespace std for C++98.])
      fi
    fi

    # Option parsed, now set things appropriately.
    if test x"$glibcxx_cv_c99_math_cxx98" = x"no" ||
       test x"$glibcxx_cv_c99_complex_cxx98" = x"no" ||
       test x"$glibcxx_cv_c99_stdio_cxx98" = x"no" ||
       test x"$glibcxx_cv_c99_stdlib_cxx98" = x"no" ||
       test x"$glibcxx_cv_c99_wchar_cxx98" = x"no"; then
      enable_c99=no;
    else
      AC_DEFINE(_GLIBCXX_USE_C99, 1,
        [Define if C99 functions or macros from <wchar.h>, <math.h>,
        <complex.h>, <stdio.h>, and <stdlib.h> can be used or exposed.])
    fi

    gcc_no_link="$ac_save_gcc_no_link"
    LIBS="$ac_save_LIBS"
    CXXFLAGS="$ac_save_CXXFLAGS"
    AC_LANG_RESTORE

    AC_LANG_SAVE
    AC_LANG_CPLUSPLUS

    # Use -std=c++11 and test again for C99 library feature in C++11 mode.
    # For the reasons given above we use -std=c++11 not -std=gnu++11.
    ac_save_CXXFLAGS="$CXXFLAGS"
    CXXFLAGS="$CXXFLAGS -std=c++11"
    ac_save_LIBS="$LIBS"
    ac_save_gcc_no_link="$gcc_no_link"

    if test x$gcc_no_link != xyes; then
      # Use -fno-exceptions to that the C driver can link these tests without
      # hitting undefined references to personality routines.
      CXXFLAGS="$CXXFLAGS -fno-exceptions"
      AC_CHECK_LIB(m, sin, [LIBS="$LIBS -lm"], [
        # Use the default compile-only tests in GCC_TRY_COMPILE_OR_LINK
        gcc_no_link=yes
      ])
    fi

    # Check for the existence of <math.h> functions used if C99 is enabled.
    AC_MSG_CHECKING([for ISO C99 support in <math.h> for C++11])
    AC_CACHE_VAL(glibcxx_cv_c99_math_cxx11, [
      GCC_TRY_COMPILE_OR_LINK(
        [#include <math.h>
         volatile double d1, d2;
         volatile int i;],
        [i = fpclassify(d1);
         i = isfinite(d1);
         i = isinf(d1);
         i = isnan(d1);
         i = isnormal(d1);
         i = signbit(d1);
         i = isgreater(d1, d2);
         i = isgreaterequal(d1, d2);
         i = isless(d1, d2);
         i = islessequal(d1, d2);
         i = islessgreater(d1, d2);
         i = islessgreater(d1, d2);
         i = isunordered(d1, d2);
        ], [glibcxx_cv_c99_math_cxx11=yes], [glibcxx_cv_c99_math_cxx11=no])
    ])
    AC_MSG_RESULT($glibcxx_cv_c99_math_cxx11)
    if test x"$glibcxx_cv_c99_math_cxx11" = x"yes"; then
      AC_DEFINE(_GLIBCXX11_USE_C99_MATH, 1,
        [Define if C99 functions or macros in <math.h> should be imported
        in <cmath> in namespace std for C++11.])
    fi

    # Check for the existence of <complex.h> complex math functions.
    # This is necessary even though libstdc++ uses the builtin versions
    # of these functions, because if the builtin cannot be used, a reference
    # to the library function is emitted.
    AC_CHECK_HEADERS(tgmath.h, ac_has_tgmath_h=yes, ac_has_tgmath_h=no)
    AC_CHECK_HEADERS(complex.h, ac_has_complex_h=yes, ac_has_complex_h=no)
    if test x"$ac_has_complex_h" = x"yes"; then
      AC_MSG_CHECKING([for ISO C99 support in <complex.h> for C++11])
      AC_CACHE_VAL(glibcxx_cv_c99_complex_cxx11, [
        GCC_TRY_COMPILE_OR_LINK(
          [#include <complex.h>
           typedef __complex__ float float_type;
           typedef __complex__ double double_type;
           typedef __complex__ long double ld_type;
           volatile float_type tmpf;
           volatile double_type tmpd;
           volatile ld_type tmpld;
           volatile float f;
           volatile double d;
           volatile long double ld;],
          [f = cabsf(tmpf);
           f = cargf(tmpf);
           tmpf = ccosf(tmpf);
           tmpf = ccoshf(tmpf);
           tmpf = cexpf(tmpf);
           tmpf = clogf(tmpf);
           tmpf = csinf(tmpf);
           tmpf = csinhf(tmpf);
           tmpf = csqrtf(tmpf);
           tmpf = ctanf(tmpf);
           tmpf = ctanhf(tmpf);
           tmpf = cpowf(tmpf, tmpf);
           tmpf = cprojf(tmpf);
           d = cabs(tmpd);
           d = carg(tmpd);
           tmpd = ccos(tmpd);
           tmpd = ccosh(tmpd);
           tmpd = cexp(tmpd);
           tmpd = clog(tmpd);
           tmpd = csin(tmpd);
           tmpd = csinh(tmpd);
           tmpd = csqrt(tmpd);
           tmpd = ctan(tmpd);
           tmpd = ctanh(tmpd);
           tmpd = cpow(tmpd, tmpd);
           tmpd = cproj(tmpd);
           ld = cabsl(tmpld);
           ld = cargl(tmpld);
           tmpld = ccosl(tmpld);
           tmpld = ccoshl(tmpld);
           tmpld = cexpl(tmpld);
           tmpld = clogl(tmpld);
           tmpld = csinl(tmpld);
           tmpld = csinhl(tmpld);
           tmpld = csqrtl(tmpld);
           tmpld = ctanl(tmpld);
           tmpld = ctanhl(tmpld);
           tmpld = cpowl(tmpld, tmpld);
           tmpld = cprojl(tmpld);
          ], [glibcxx_cv_c99_complex_cxx11=yes], [glibcxx_cv_c99_complex_cxx11=no])
      ])
    fi
    AC_MSG_RESULT($glibcxx_cv_c99_complex_cxx11)
    if test x"$glibcxx_cv_c99_complex_cxx11" = x"yes"; then
      AC_DEFINE(_GLIBCXX11_USE_C99_COMPLEX, 1,
        [Define if C99 functions in <complex.h> should be used in
        <complex> for C++11. Using compiler builtins for these functions
        requires corresponding C99 library functions to be present.])
    fi

    # Check for the existence in <stdio.h> of vscanf, et. al.
    AC_MSG_CHECKING([for ISO C99 support in <stdio.h> for C++11])
    AC_CACHE_VAL(glibcxx_cv_c99_stdio_cxx11, [
      GCC_TRY_COMPILE_OR_LINK(
        [#include <stdio.h>
         #include <stdarg.h>
         void foo(char* fmt, ...)
         {
           va_list args; va_start(args, fmt);
           vfscanf(stderr, "%i", args);
           vscanf("%i", args);
           vsnprintf(fmt, 0, "%i", args);
           vsscanf(fmt, "%i", args);
           snprintf(fmt, 0, "%i");
         }], [],
        [glibcxx_cv_c99_stdio_cxx11=yes], [glibcxx_cv_c99_stdio_cxx11=no])
    ])
    AC_MSG_RESULT($glibcxx_cv_c99_stdio_cxx11)
    if test x"$glibcxx_cv_c99_stdio_cxx11" = x"yes"; then
      AC_DEFINE(_GLIBCXX11_USE_C99_STDIO, 1,
        [Define if C99 functions or macros in <stdio.h> should be imported
        in <cstdio> in namespace std for C++11.])
    fi

    # Check for the existence in <stdlib.h> of lldiv_t, et. al.
    AC_MSG_CHECKING([for ISO C99 support in <stdlib.h> for C++11])
    AC_CACHE_VAL(glibcxx_cv_c99_stdlib_cxx11, [
      GCC_TRY_COMPILE_OR_LINK(
        [#include <stdlib.h>
         volatile float f;
         volatile long double ld;
         volatile unsigned long long ll;
         lldiv_t mydivt;],
        [char* tmp;
         f = strtof("gnu", &tmp);
         ld = strtold("gnu", &tmp);
         ll = strtoll("gnu", &tmp, 10);
         ll = strtoull("gnu", &tmp, 10);
         ll = llabs(10);
         mydivt = lldiv(10,1);
         ll = mydivt.quot;
         ll = mydivt.rem;
         ll = atoll("10");
         _Exit(0);
        ], [glibcxx_cv_c99_stdlib_cxx11=yes], [glibcxx_cv_c99_stdlib_cxx11=no])
    ])
    AC_MSG_RESULT($glibcxx_cv_c99_stdlib_cxx11)
    if test x"$glibcxx_cv_c99_stdlib_cxx11" = x"yes"; then
      AC_DEFINE(_GLIBCXX11_USE_C99_STDLIB, 1,
        [Define if C99 functions or macros in <stdlib.h> should be imported
        in <cstdlib> in namespace std for C++11.])
    fi

    # Check for the existence in <wchar.h> of wcstold, etc.
    if test x"$ac_has_wchar_h" = xyes &&
       test x"$ac_has_wctype_h" = xyes; then
      AC_MSG_CHECKING([for ISO C99 support in <wchar.h> for C++11])
      AC_CACHE_VAL(glibcxx_cv_c99_wchar_cxx11, [
        AC_TRY_COMPILE([#include <wchar.h>
          namespace test
          {
            using ::wcstold;
            using ::wcstoll;
            using ::wcstoull;
          }
        ], [], [glibcxx_cv_c99_wchar_cxx11=yes], [glibcxx_cv_c99_wchar_cxx11=no])
      ])

      # Checks for wide character functions that may not be present.
      # Injection of these is wrapped with guard macros.
      # NB: only put functions here, instead of immediately above, if
      # absolutely necessary.
      AC_TRY_COMPILE([#include <wchar.h>
        namespace test { using ::vfwscanf; }], [],
        [AC_DEFINE(HAVE_VFWSCANF, 1, [Defined if vfwscanf exists.])], [])

      AC_TRY_COMPILE([#include <wchar.h>
        namespace test { using ::vswscanf; }], [],
        [AC_DEFINE(HAVE_VSWSCANF, 1, [Defined if vswscanf exists.])], [])

      AC_TRY_COMPILE([#include <wchar.h>
        namespace test { using ::vwscanf; }], [],
        [AC_DEFINE(HAVE_VWSCANF, 1, [Defined if vwscanf exists.])], [])

      AC_TRY_COMPILE([#include <wchar.h>
        namespace test { using ::wcstof; }], [],
        [AC_DEFINE(HAVE_WCSTOF, 1, [Defined if wcstof exists.])], [])

      AC_TRY_COMPILE([#include <wctype.h>],
        [wint_t t; int i = iswblank(t);],
        [AC_DEFINE(HAVE_ISWBLANK, 1, [Defined if iswblank exists.])], [])

      AC_MSG_RESULT($glibcxx_cv_c99_wchar_cxx11)
      if test x"$glibcxx_cv_c99_wchar_cxx11" = x"yes"; then
        AC_DEFINE(_GLIBCXX11_USE_C99_WCHAR, 1,
          [Define if C99 functions or macros in <wchar.h> should be imported
          in <cwchar> in namespace std for C++11.])
      fi
    fi

    gcc_no_link="$ac_save_gcc_no_link"
    LIBS="$ac_save_LIBS"
    CXXFLAGS="$ac_save_CXXFLAGS"
    AC_LANG_RESTORE
  fi

  AC_MSG_CHECKING([for fully enabled ISO C99 support])
  AC_MSG_RESULT($enable_c99)
])


dnl
dnl Check for clock_gettime, nanosleep and sched_yield, used in the
dnl implementation of 20.11.7 [time.clock], and 30.3.2 [thread.thread.this]
dnl in the C++11 standard.
dnl
dnl --enable-libstdcxx-time
dnl --enable-libstdcxx-time=yes
dnl        checks for the availability of monotonic and realtime clocks,
dnl        nanosleep and sched_yield in libc and libposix4 and, if needed,
dnl        links in the latter.
dnl --enable-libstdcxx-time=rt
dnl        also searches (and, if needed, links) librt.  Note that this is
dnl        not always desirable because, in glibc 2.16 and earlier, for
dnl        example, in turn it triggers the linking of libpthread too,
dnl        which activates locking,
dnl        a large overhead for single-thread programs.
dnl --enable-libstdcxx-time=no
dnl --disable-libstdcxx-time
dnl        disables the checks completely
dnl
dnl N.B. Darwin provides nanosleep but doesn't support the whole POSIX
dnl Timers option, so doesn't define _POSIX_TIMERS. Because the test
dnl below fails Darwin unconditionally defines _GLIBCXX_USE_NANOSLEEP in
dnl os_defines.h and also defines _GLIBCXX_USE_SCHED_YIELD.
dnl
AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_TIME], [

  GLIBCXX_ENABLE(libstdcxx-time,auto,[[[=KIND]]],
    [use KIND for check type],
    [permit yes|no|rt])

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"
  ac_save_LIBS="$LIBS"

  ac_has_clock_monotonic=no
  ac_has_clock_realtime=no
  ac_has_nanosleep=no
  ac_has_sched_yield=no

  if test x"$enable_libstdcxx_time" = x"auto"; then

    case "${target_os}" in
      cygwin*)
        ac_has_nanosleep=yes
        ;;
      darwin*)
        ac_has_nanosleep=yes
        ac_has_sched_yield=yes
        ;;
      # VxWorks has nanosleep as soon as the kernel is configured with
      # INCLUDE_POSIX_TIMERS, which is normally/most-often the case.
      vxworks*)
        ac_has_nanosleep=yes
        ;;
      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
        # Don't use link test for freestanding library, in case gcc_no_link=yes
        if test x"$is_hosted" = xyes; then
          # Versions of glibc before 2.17 needed -lrt for clock_gettime.
          AC_SEARCH_LIBS(clock_gettime, [rt])
          if test x"$ac_cv_search_clock_gettime" = x"none required"; then
            ac_has_clock_monotonic=yes
            ac_has_clock_realtime=yes
          fi
        fi
        ac_has_nanosleep=yes
        ac_has_sched_yield=yes
        ;;
      freebsd*|netbsd*|dragonfly*|rtems*)
        ac_has_clock_monotonic=yes
        ac_has_clock_realtime=yes
        ac_has_nanosleep=yes
        ac_has_sched_yield=yes
        ;;
      openbsd*)
        ac_has_clock_monotonic=yes
        ac_has_clock_realtime=yes
        ac_has_nanosleep=yes
        ;;
      solaris*)
        GLIBCXX_LIBS="$GLIBCXX_LIBS -lrt"
        ac_has_clock_monotonic=yes
        ac_has_clock_realtime=yes
        ac_has_nanosleep=yes
        ac_has_sched_yield=yes
        ;;
      uclinux*)
        ac_has_nanosleep=yes
        ac_has_sched_yield=yes
    esac

  elif test x"$enable_libstdcxx_time" != x"no"; then

    if test x"$enable_libstdcxx_time" = x"rt"; then
      AC_SEARCH_LIBS(clock_gettime, [rt posix4])
      AC_SEARCH_LIBS(nanosleep, [rt posix4])
    else
      AC_SEARCH_LIBS(clock_gettime, [posix4])
      AC_SEARCH_LIBS(nanosleep, [posix4])
    fi

    case "$ac_cv_search_clock_gettime" in
      -l*) GLIBCXX_LIBS=$ac_cv_search_clock_gettime
      ;;
    esac
    case "$ac_cv_search_nanosleep" in
      -l*) GLIBCXX_LIBS="$GLIBCXX_LIBS $ac_cv_search_nanosleep"
      ;;
    esac

    AC_SEARCH_LIBS(sched_yield, [rt posix4])

    case "$ac_cv_search_sched_yield" in
      -lposix4*)
      GLIBCXX_LIBS="$GLIBCXX_LIBS $ac_cv_search_sched_yield"
      ac_has_sched_yield=yes
      ;;
      -lrt*)
      if test x"$enable_libstdcxx_time" = x"rt"; then
	GLIBCXX_LIBS="$GLIBCXX_LIBS $ac_cv_search_sched_yield"
        ac_has_sched_yield=yes
      fi
      ;;
      *)
      ac_has_sched_yield=yes
      ;;
    esac

    AC_CHECK_HEADERS(unistd.h, ac_has_unistd_h=yes, ac_has_unistd_h=no)

    if test x"$ac_has_unistd_h" = x"yes"; then
      AC_MSG_CHECKING([for monotonic clock])
      AC_TRY_LINK(
	[#include <unistd.h>
	 #include <time.h>
	],
	[#if _POSIX_TIMERS > 0 && defined(_POSIX_MONOTONIC_CLOCK)
	  timespec tp;
	 #endif
	  clock_gettime(CLOCK_MONOTONIC, &tp);
	], [ac_has_clock_monotonic=yes], [ac_has_clock_monotonic=no])

      AC_MSG_RESULT($ac_has_clock_monotonic)

      AC_MSG_CHECKING([for realtime clock])
      AC_TRY_LINK(
	[#include <unistd.h>
	 #include <time.h>
	],
	[#if _POSIX_TIMERS > 0
	  timespec tp;
	 #endif
	  clock_gettime(CLOCK_REALTIME, &tp);
	], [ac_has_clock_realtime=yes], [ac_has_clock_realtime=no])

      AC_MSG_RESULT($ac_has_clock_realtime)

      AC_MSG_CHECKING([for nanosleep])
      AC_TRY_LINK(
	[#include <unistd.h>
	 #include <time.h>
	],
	[#if _POSIX_TIMERS > 0
	  timespec tp;
	 #endif
	  nanosleep(&tp, 0);
	], [ac_has_nanosleep=yes], [ac_has_nanosleep=no])

      AC_MSG_RESULT($ac_has_nanosleep)
    fi
  fi

  if test x"$ac_has_clock_monotonic" != x"yes"; then
    case ${target_os} in
      linux* | uclinux*)
	AC_MSG_CHECKING([for clock_gettime syscall])
	AC_TRY_COMPILE(
	  [#include <unistd.h>
	   #include <time.h>
	   #include <sys/syscall.h>
	  ],
	  [#if _POSIX_TIMERS > 0 && defined(_POSIX_MONOTONIC_CLOCK)
	    timespec tp;
	   #endif
	   syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &tp);
	   syscall(SYS_clock_gettime, CLOCK_REALTIME, &tp);
	  ], [ac_has_clock_monotonic_syscall=yes], [ac_has_clock_monotonic_syscall=no])
	AC_MSG_RESULT($ac_has_clock_monotonic_syscall)
	if test x"$ac_has_clock_monotonic_syscall" = x"yes"; then
	  AC_DEFINE(_GLIBCXX_USE_CLOCK_GETTIME_SYSCALL, 1,
	  [ Defined if clock_gettime syscall has monotonic and realtime clock support. ])
	  ac_has_clock_monotonic=yes
	  ac_has_clock_realtime=yes
	fi;;
    esac
  fi

  if test x"$ac_has_clock_monotonic" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_CLOCK_MONOTONIC, 1,
      [ Defined if clock_gettime has monotonic clock support. ])
  fi

  if test x"$ac_has_clock_realtime" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_CLOCK_REALTIME, 1,
      [ Defined if clock_gettime has realtime clock support. ])
  fi

  if test x"$ac_has_sched_yield" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_SCHED_YIELD, 1,
              [ Defined if sched_yield is available. ])
  fi

  if test x"$ac_has_nanosleep" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_NANOSLEEP, 1,
      [ Defined if nanosleep is available. ])
  else
      AC_MSG_CHECKING([for sleep])
      AC_TRY_COMPILE([#include <unistd.h>],
                     [sleep(1)],
                     [ac_has_sleep=yes],[ac_has_sleep=no])
      if test x"$ac_has_sleep" = x"yes"; then
        AC_DEFINE(HAVE_SLEEP,1, [Defined if sleep exists.])
      fi
      AC_MSG_RESULT($ac_has_sleep)
      AC_MSG_CHECKING([for usleep])
      AC_TRY_COMPILE([#include <unistd.h>],
                     [sleep(1);
                      usleep(100);],
                     [ac_has_usleep=yes],[ac_has_usleep=no])
      if test x"$ac_has_usleep" = x"yes"; then
        AC_DEFINE(HAVE_USLEEP,1, [Defined if usleep exists.])
      fi
      AC_MSG_RESULT($ac_has_usleep)
  fi

  if test x"$ac_has_nanosleep$ac_has_sleep" = x"nono"; then
      AC_MSG_CHECKING([for Sleep])
      AC_TRY_COMPILE([#include <windows.h>],
                     [Sleep(1)],
                     [ac_has_win32_sleep=yes],[ac_has_win32_sleep=no])
      if test x"$ac_has_win32_sleep" = x"yes"; then
        AC_DEFINE(HAVE_WIN32_SLEEP,1, [Defined if Sleep exists.])
      fi
      AC_MSG_RESULT($ac_has_win32_sleep)
  fi

  AC_SUBST(GLIBCXX_LIBS)

  CXXFLAGS="$ac_save_CXXFLAGS"
  LIBS="$ac_save_LIBS"
  AC_LANG_RESTORE
])

dnl
dnl Check for gettimeofday, used in the implementation of 20.11.7
dnl [time.clock] in the C++11 standard.
dnl
AC_DEFUN([GLIBCXX_CHECK_GETTIMEOFDAY], [

  AC_MSG_CHECKING([for gettimeofday])

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  ac_has_gettimeofday=no;
  AC_CHECK_HEADERS(sys/time.h, ac_has_sys_time_h=yes, ac_has_sys_time_h=no)
  if test x"$ac_has_sys_time_h" = x"yes"; then
    AC_MSG_CHECKING([for gettimeofday])
    GCC_TRY_COMPILE_OR_LINK([#include <sys/time.h>],
      [timeval tv; gettimeofday(&tv, 0);],
      [ac_has_gettimeofday=yes], [ac_has_gettimeofday=no])

    AC_MSG_RESULT($ac_has_gettimeofday)
  fi

  if test x"$ac_has_gettimeofday" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_GETTIMEOFDAY, 1,
      [ Defined if gettimeofday is available. ])
  fi

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check for ISO/IEC 9899:1999 "C99" support to ISO/IEC DTR 19768 "TR1"
dnl facilities in Chapter 8, "C compatibility".
dnl
AC_DEFUN([GLIBCXX_CHECK_C99_TR1], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS

  # Use -std=c++98 because the default (-std=gnu++98) leaves __STRICT_ANSI__
  # undefined and fake C99 facilities may be spuriously enabled.
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -std=c++98"

  # Check for the existence of <complex.h> complex math functions used
  # by tr1/complex.
  AC_CHECK_HEADERS(complex.h, ac_has_complex_h=yes, ac_has_complex_h=no)
  ac_c99_complex_tr1=no;
  if test x"$ac_has_complex_h" = x"yes"; then
    AC_MSG_CHECKING([for ISO C99 support to TR1 in <complex.h>])
    AC_TRY_COMPILE([#include <complex.h>],
		   [typedef __complex__ float float_type; float_type tmpf;
		    cacosf(tmpf);
		    casinf(tmpf);
		    catanf(tmpf);
		    cacoshf(tmpf);
		    casinhf(tmpf);
		    catanhf(tmpf);
		    typedef __complex__ double double_type; double_type tmpd;
		    cacos(tmpd);
		    casin(tmpd);
		    catan(tmpd);
		    cacosh(tmpd);
		    casinh(tmpd);
		    catanh(tmpd);
		    typedef __complex__ long double ld_type; ld_type tmpld;
		    cacosl(tmpld);
		    casinl(tmpld);
		    catanl(tmpld);
		    cacoshl(tmpld);
		    casinhl(tmpld);
		    catanhl(tmpld);
		   ],[ac_c99_complex_tr1=yes], [ac_c99_complex_tr1=no])
  fi
  AC_MSG_RESULT($ac_c99_complex_tr1)
  if test x"$ac_c99_complex_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_COMPLEX_TR1, 1,
	      [Define if C99 functions in <complex.h> should be used in
	      <tr1/complex>. Using compiler builtins for these functions
	      requires corresponding C99 library functions to be present.])
  fi

  # Check for the existence of <ctype.h> functions.
  AC_MSG_CHECKING([for ISO C99 support to TR1 in <ctype.h>])
  AC_CACHE_VAL(glibcxx_cv_c99_ctype_tr1, [
  AC_TRY_COMPILE([#include <ctype.h>],
		 [int ch;
		  int ret;
		  ret = isblank(ch);
		 ],[glibcxx_cv_c99_ctype_tr1=yes],
		   [glibcxx_cv_c99_ctype_tr1=no])
  ])
  AC_MSG_RESULT($glibcxx_cv_c99_ctype_tr1)
  if test x"$glibcxx_cv_c99_ctype_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_CTYPE_TR1, 1,
	      [Define if C99 functions in <ctype.h> should be imported in
	      <tr1/cctype> in namespace std::tr1.])
  fi

  # Check for the existence of <fenv.h> functions.
  AC_CHECK_HEADERS(fenv.h, ac_has_fenv_h=yes, ac_has_fenv_h=no)
  ac_c99_fenv_tr1=no;
  if test x"$ac_has_fenv_h" = x"yes"; then
    AC_MSG_CHECKING([for ISO C99 support to TR1 in <fenv.h>])
    AC_TRY_COMPILE([#include <fenv.h>],
		   [int except, mode;
		    fexcept_t* pflag;
		    fenv_t* penv;
		    int ret;
		    ret = feclearexcept(except);
		    ret = fegetexceptflag(pflag, except);
		    ret = feraiseexcept(except);
		    ret = fesetexceptflag(pflag, except);
		    ret = fetestexcept(except);
		    ret = fegetround();
		    ret = fesetround(mode);
		    ret = fegetenv(penv);
		    ret = feholdexcept(penv);
		    ret = fesetenv(penv);
		    ret = feupdateenv(penv);
		   ],[ac_c99_fenv_tr1=yes], [ac_c99_fenv_tr1=no])
  fi
  AC_MSG_RESULT($ac_c99_fenv_tr1)
  if test x"$ac_c99_fenv_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_FENV_TR1, 1,
	      [Define if C99 functions in <fenv.h> should be imported in
	      <tr1/cfenv> in namespace std::tr1.])
  fi

  # Check for the existence of <stdint.h> types.
  AC_MSG_CHECKING([for ISO C99 support to TR1 in <stdint.h>])
  AC_CACHE_VAL(glibcxx_cv_c99_stdint_tr1, [
  AC_TRY_COMPILE([#define __STDC_LIMIT_MACROS
		  #define __STDC_CONSTANT_MACROS
		  #include <stdint.h>],
		 [typedef int8_t          my_int8_t;
		  my_int8_t               i8 = INT8_MIN;
		  i8 = INT8_MAX;
		  typedef int16_t         my_int16_t;
		  my_int16_t              i16 = INT16_MIN;
		  i16 = INT16_MAX;
		  typedef int32_t         my_int32_t;
		  my_int32_t              i32 = INT32_MIN;
		  i32 = INT32_MAX;
		  typedef int64_t         my_int64_t;
		  my_int64_t              i64 = INT64_MIN;
		  i64 = INT64_MAX;
		  typedef int_fast8_t     my_int_fast8_t;
		  my_int_fast8_t          if8 = INT_FAST8_MIN;
		  if8 = INT_FAST8_MAX;
		  typedef int_fast16_t    my_int_fast16_t;
		  my_int_fast16_t         if16 = INT_FAST16_MIN;
		  if16 = INT_FAST16_MAX;
		  typedef int_fast32_t    my_int_fast32_t;
		  my_int_fast32_t         if32 = INT_FAST32_MIN;
		  if32 = INT_FAST32_MAX;
		  typedef int_fast64_t    my_int_fast64_t;
		  my_int_fast64_t         if64 = INT_FAST64_MIN;
		  if64 = INT_FAST64_MAX;
		  typedef int_least8_t    my_int_least8_t;
		  my_int_least8_t         il8 = INT_LEAST8_MIN;
		  il8 = INT_LEAST8_MAX;
		  typedef int_least16_t   my_int_least16_t;
		  my_int_least16_t        il16 = INT_LEAST16_MIN;
		  il16 = INT_LEAST16_MAX;
		  typedef int_least32_t   my_int_least32_t;
		  my_int_least32_t        il32 = INT_LEAST32_MIN;
		  il32 = INT_LEAST32_MAX;
		  typedef int_least64_t   my_int_least64_t;
		  my_int_least64_t        il64 = INT_LEAST64_MIN;
		  il64 = INT_LEAST64_MAX;
		  typedef intmax_t        my_intmax_t;
		  my_intmax_t             im = INTMAX_MAX;
		  im = INTMAX_MIN;
		  typedef intptr_t        my_intptr_t;
		  my_intptr_t             ip = INTPTR_MAX;
		  ip = INTPTR_MIN;
		  typedef uint8_t         my_uint8_t;
		  my_uint8_t              ui8 = UINT8_MAX;
		  ui8 = UINT8_MAX;
		  typedef uint16_t        my_uint16_t;
		  my_uint16_t             ui16 = UINT16_MAX;
		  ui16 = UINT16_MAX;
		  typedef uint32_t        my_uint32_t;
		  my_uint32_t             ui32 = UINT32_MAX;
		  ui32 = UINT32_MAX;
		  typedef uint64_t        my_uint64_t;
		  my_uint64_t             ui64 = UINT64_MAX;
		  ui64 = UINT64_MAX;
		  typedef uint_fast8_t    my_uint_fast8_t;
		  my_uint_fast8_t         uif8 = UINT_FAST8_MAX;
		  uif8 = UINT_FAST8_MAX;
		  typedef uint_fast16_t   my_uint_fast16_t;
		  my_uint_fast16_t        uif16 = UINT_FAST16_MAX;
		  uif16 = UINT_FAST16_MAX;
		  typedef uint_fast32_t   my_uint_fast32_t;
		  my_uint_fast32_t        uif32 = UINT_FAST32_MAX;
		  uif32 = UINT_FAST32_MAX;
		  typedef uint_fast64_t   my_uint_fast64_t;
		  my_uint_fast64_t        uif64 = UINT_FAST64_MAX;
		  uif64 = UINT_FAST64_MAX;
		  typedef uint_least8_t   my_uint_least8_t;
		  my_uint_least8_t        uil8 = UINT_LEAST8_MAX;
		  uil8 = UINT_LEAST8_MAX;
		  typedef uint_least16_t  my_uint_least16_t;
		  my_uint_least16_t       uil16 = UINT_LEAST16_MAX;
		  uil16 = UINT_LEAST16_MAX;
		  typedef uint_least32_t  my_uint_least32_t;
		  my_uint_least32_t       uil32 = UINT_LEAST32_MAX;
		  uil32 = UINT_LEAST32_MAX;
		  typedef uint_least64_t  my_uint_least64_t;
		  my_uint_least64_t       uil64 = UINT_LEAST64_MAX;
		  uil64 = UINT_LEAST64_MAX;
		  typedef uintmax_t       my_uintmax_t;
		  my_uintmax_t            uim = UINTMAX_MAX;
		  uim = UINTMAX_MAX;
		  typedef uintptr_t       my_uintptr_t;
		  my_uintptr_t            uip = UINTPTR_MAX;
		  uip = UINTPTR_MAX;
		 ],[glibcxx_cv_c99_stdint_tr1=yes],
		   [glibcxx_cv_c99_stdint_tr1=no])
  ])
  AC_MSG_RESULT($glibcxx_cv_c99_stdint_tr1)
  if test x"$glibcxx_cv_c99_stdint_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_STDINT_TR1, 1,
	      [Define if C99 types in <stdint.h> should be imported in
	      <tr1/cstdint> in namespace std::tr1.])
  fi

  # Check for the existence of <math.h> functions.
  AC_MSG_CHECKING([for ISO C99 support to TR1 in <math.h>])
  AC_CACHE_VAL(glibcxx_cv_c99_math_tr1, [
  AC_TRY_COMPILE([#include <math.h>],
		 [typedef double_t  my_double_t;
		  typedef float_t   my_float_t;
		  acosh(0.0);
		  acoshf(0.0f);
		  acoshl(0.0l);
		  asinh(0.0);
		  asinhf(0.0f);
		  asinhl(0.0l);
		  atanh(0.0);
		  atanhf(0.0f);
		  atanhl(0.0l);
		  cbrt(0.0);
		  cbrtf(0.0f);
		  cbrtl(0.0l);
		  copysign(0.0, 0.0);
		  copysignf(0.0f, 0.0f);
		  copysignl(0.0l, 0.0l);
		  erf(0.0);
		  erff(0.0f);
		  erfl(0.0l);
		  erfc(0.0);
		  erfcf(0.0f);
		  erfcl(0.0l);
		  exp2(0.0);
		  exp2f(0.0f);
		  exp2l(0.0l);
		  expm1(0.0);
		  expm1f(0.0f);
		  expm1l(0.0l);
		  fdim(0.0, 0.0);
		  fdimf(0.0f, 0.0f);
		  fdiml(0.0l, 0.0l);
		  fma(0.0, 0.0, 0.0);
		  fmaf(0.0f, 0.0f, 0.0f);
		  fmal(0.0l, 0.0l, 0.0l);
		  fmax(0.0, 0.0);
		  fmaxf(0.0f, 0.0f);
		  fmaxl(0.0l, 0.0l);
		  fmin(0.0, 0.0);
		  fminf(0.0f, 0.0f);
		  fminl(0.0l, 0.0l);
		  hypot(0.0, 0.0);
		  hypotf(0.0f, 0.0f);
		  hypotl(0.0l, 0.0l);
		  ilogb(0.0);
		  ilogbf(0.0f);
		  ilogbl(0.0l);
		  lgamma(0.0);
		  lgammaf(0.0f);
		  lgammal(0.0l);
		  #ifndef __APPLE__ /* see below */
		  llrint(0.0);
		  llrintf(0.0f);
		  llrintl(0.0l);
		  llround(0.0);
		  llroundf(0.0f);
		  llroundl(0.0l);
		  #endif
		  log1p(0.0);
		  log1pf(0.0f);
		  log1pl(0.0l);
		  log2(0.0);
		  log2f(0.0f);
		  log2l(0.0l);
		  logb(0.0);
		  logbf(0.0f);
		  logbl(0.0l);
		  lrint(0.0);
		  lrintf(0.0f);
		  lrintl(0.0l);
		  lround(0.0);
		  lroundf(0.0f);
		  lroundl(0.0l);
		  nan(0);
		  nanf(0);
		  nanl(0);
		  nearbyint(0.0);
		  nearbyintf(0.0f);
		  nearbyintl(0.0l);
		  nextafter(0.0, 0.0);
		  nextafterf(0.0f, 0.0f);
		  nextafterl(0.0l, 0.0l);
		  nexttoward(0.0, 0.0);
		  nexttowardf(0.0f, 0.0f);
		  nexttowardl(0.0l, 0.0l);
		  remainder(0.0, 0.0);
		  remainderf(0.0f, 0.0f);
		  remainderl(0.0l, 0.0l);
		  remquo(0.0, 0.0, 0);
		  remquof(0.0f, 0.0f, 0);
		  remquol(0.0l, 0.0l, 0);
		  rint(0.0);
		  rintf(0.0f);
		  rintl(0.0l);
		  round(0.0);
		  roundf(0.0f);
		  roundl(0.0l);
		  scalbln(0.0, 0l);
		  scalblnf(0.0f, 0l);
		  scalblnl(0.0l, 0l);
		  scalbn(0.0, 0);
		  scalbnf(0.0f, 0);
		  scalbnl(0.0l, 0);
		  tgamma(0.0);
		  tgammaf(0.0f);
		  tgammal(0.0l);
		  trunc(0.0);
		  truncf(0.0f);
		  truncl(0.0l);
		 ],[glibcxx_cv_c99_math_tr1=yes], [glibcxx_cv_c99_math_tr1=no])
  ])
  AC_MSG_RESULT($glibcxx_cv_c99_math_tr1)
  if test x"$glibcxx_cv_c99_math_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_MATH_TR1, 1,
	      [Define if C99 functions or macros in <math.h> should be imported
	      in <tr1/cmath> in namespace std::tr1.])

    case "${target_os}" in
      darwin*)
        AC_MSG_CHECKING([for ISO C99 rounding functions in <math.h>])
        AC_CACHE_VAL(glibcxx_cv_c99_math_llround, [
          AC_TRY_COMPILE([#include <math.h>],
		 [llrint(0.0);
		  llrintf(0.0f);
		  llrintl(0.0l);
		  llround(0.0);
		  llroundf(0.0f);
		  llroundl(0.0l);
		 ],
		 [glibcxx_cv_c99_math_llround=yes],
		 [glibcxx_cv_c99_math_llround=no])
          ])
	AC_MSG_RESULT($glibcxx_cv_c99_math_llround)
        ;;
    esac
    if test x"$glibcxx_cv_c99_math_llround" = x"no"; then
      AC_DEFINE(_GLIBCXX_NO_C99_ROUNDING_FUNCS, 1,
		[Define if C99 llrint and llround functions are missing from <math.h>.])
    fi
  fi

  # Check for the existence of <inttypes.h> functions (NB: doesn't make
  # sense if the glibcxx_cv_c99_stdint_tr1 check fails, per C99, 7.8/1).
  ac_c99_inttypes_tr1=no;
  if test x"$glibcxx_cv_c99_stdint_tr1" = x"yes"; then
    AC_MSG_CHECKING([for ISO C99 support to TR1 in <inttypes.h>])
    AC_TRY_COMPILE([#include <inttypes.h>],
		   [intmax_t i, numer, denom, base;
		    const char* s;
		    char** endptr;
		    intmax_t ret = imaxabs(i);
		    imaxdiv_t dret = imaxdiv(numer, denom);
		    ret = strtoimax(s, endptr, base);
		    uintmax_t uret = strtoumax(s, endptr, base);
		   ],[ac_c99_inttypes_tr1=yes], [ac_c99_inttypes_tr1=no])
  fi
  AC_MSG_RESULT($ac_c99_inttypes_tr1)
  if test x"$ac_c99_inttypes_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_INTTYPES_TR1, 1,
	      [Define if C99 functions in <inttypes.h> should be imported in
	      <tr1/cinttypes> in namespace std::tr1.])
  fi

  # Check for the existence of wchar_t <inttypes.h> functions (NB: doesn't
  # make sense if the glibcxx_cv_c99_stdint_tr1 check fails, per C99, 7.8/1).
  ac_c99_inttypes_wchar_t_tr1=no;
  if test x"$glibcxx_cv_c99_stdint_tr1" = x"yes"; then
    AC_MSG_CHECKING([for wchar_t ISO C99 support to TR1 in <inttypes.h>])
    AC_TRY_COMPILE([#include <inttypes.h>],
		   [intmax_t base;
		    const wchar_t* s;
		    wchar_t** endptr;
		    intmax_t ret = wcstoimax(s, endptr, base);
		    uintmax_t uret = wcstoumax(s, endptr, base);
		   ],[ac_c99_inttypes_wchar_t_tr1=yes],
		     [ac_c99_inttypes_wchar_t_tr1=no])
  fi
  AC_MSG_RESULT($ac_c99_inttypes_wchar_t_tr1)
  if test x"$ac_c99_inttypes_wchar_t_tr1" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C99_INTTYPES_WCHAR_T_TR1, 1,
	      [Define if wchar_t C99 functions in <inttypes.h> should be
	      imported in <tr1/cinttypes> in namespace std::tr1.])
  fi

  # Check for the existence of the <stdbool.h> header.
  AC_CHECK_HEADERS(stdbool.h)

  # Check for the existence of the <stdalign.h> header.
  AC_CHECK_HEADERS(stdalign.h)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check for uchar.h and usability.
dnl
AC_DEFUN([GLIBCXX_CHECK_UCHAR_H], [

  # Test uchar.h.
  AC_CHECK_HEADERS(uchar.h, ac_has_uchar_h=yes, ac_has_uchar_h=no)

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -std=c++11"

  if test x"$ac_has_uchar_h" = x"yes"; then
    AC_MSG_CHECKING([for ISO C11 support for <uchar.h>])
    AC_TRY_COMPILE([#include <uchar.h>
		    #ifdef __STDC_UTF_16__
		    long i = __STDC_UTF_16__;
		    #endif
		    #ifdef __STDC_UTF_32__
		    long j = __STDC_UTF_32__;
		    #endif
		    namespace test
		    {
		      using ::c16rtomb;
		      using ::c32rtomb;
		      using ::mbrtoc16;
		      using ::mbrtoc32;
		    }
		   ],
		   [], [ac_c11_uchar_cxx11=yes], [ac_c11_uchar_cxx11=no])
  else
    ac_c11_uchar_cxx11=no
  fi
  AC_MSG_RESULT($ac_c11_uchar_cxx11)
  if test x"$ac_c11_uchar_cxx11" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_C11_UCHAR_CXX11, 1,
	      [Define if C11 functions in <uchar.h> should be imported into
	      namespace std in <cuchar>.])
  fi

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])


dnl
dnl Check whether "/dev/random" and "/dev/urandom" are available for
dnl class std::random_device from C++ 2011 [rand.device], and
dnl random_device of "TR1" (Chapter 5.1, "Random number generation").
dnl
AC_DEFUN([GLIBCXX_CHECK_DEV_RANDOM], [

  AC_MSG_CHECKING([for "/dev/random" and "/dev/urandom" for std::random_device])
  AC_CACHE_VAL(glibcxx_cv_dev_random, [
    if test -r /dev/random && test -r /dev/urandom; then
  ## For MSys environment the test above is detected as false-positive
  ## on mingw-targets.  So disable it explicitly for them.
      case ${target_os} in
	*mingw*) glibcxx_cv_dev_random=no ;;
	*) glibcxx_cv_dev_random=yes ;;
      esac
    else
      glibcxx_cv_dev_random=no;
    fi
  ])
  AC_MSG_RESULT($glibcxx_cv_dev_random)

  if test x"$glibcxx_cv_dev_random" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_DEV_RANDOM, 1,
	      [Define if /dev/random and /dev/urandom are available for
	       std::random_device.])
    AC_DEFINE(_GLIBCXX_USE_RANDOM_TR1, 1,
	      [Define if /dev/random and /dev/urandom are available for
	       the random_device of TR1 (Chapter 5.1).])
  fi

])

dnl
dnl Compute the EOF, SEEK_CUR, and SEEK_END integer constants.
dnl
AC_DEFUN([GLIBCXX_COMPUTE_STDIO_INTEGER_CONSTANTS], [

  AC_CACHE_CHECK([for the value of EOF], glibcxx_cv_stdio_eof, [
  AC_COMPUTE_INT([glibcxx_cv_stdio_eof], [[EOF]],
		 [#include <stdio.h>],
		 [AC_MSG_ERROR([computing EOF failed])])
  ])
  AC_DEFINE_UNQUOTED(_GLIBCXX_STDIO_EOF, $glibcxx_cv_stdio_eof,
		     [Define to the value of the EOF integer constant.])

  AC_CACHE_CHECK([for the value of SEEK_CUR], glibcxx_cv_stdio_seek_cur, [
  AC_COMPUTE_INT([glibcxx_cv_stdio_seek_cur], [[SEEK_CUR]],
		 [#include <stdio.h>],
		 [AC_MSG_ERROR([computing SEEK_CUR failed])])
  ])
  AC_DEFINE_UNQUOTED(_GLIBCXX_STDIO_SEEK_CUR, $glibcxx_cv_stdio_seek_cur,
		     [Define to the value of the SEEK_CUR integer constant.])

  AC_CACHE_CHECK([for the value of SEEK_END], glibcxx_cv_stdio_seek_end, [
  AC_COMPUTE_INT([glibcxx_cv_stdio_seek_end], [[SEEK_END]],
		 [#include <stdio.h>],
		 [AC_MSG_ERROR([computing SEEK_END failed])])
  ])
  AC_DEFINE_UNQUOTED(_GLIBCXX_STDIO_SEEK_END, $glibcxx_cv_stdio_seek_end,
		     [Define to the value of the SEEK_END integer constant.])
])

dnl
dnl Check whether required C++ overloads are present in <stdio.h>.
dnl
AC_DEFUN([GLIBCXX_CHECK_STDIO_PROTO], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  # Use C++11 because a conforming <stdio.h> won't define gets for C++14,
  # and we don't need a declaration for C++14 anyway.
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -std=gnu++11"

  AC_MSG_CHECKING([for gets declaration])
  AC_CACHE_VAL(glibcxx_cv_gets, [
  AC_COMPILE_IFELSE([AC_LANG_SOURCE(
	  [#include <stdio.h>
	   namespace test
	   {
              using ::gets;
	   }
	])],
	[glibcxx_cv_gets=yes],
	[glibcxx_cv_gets=no]
      )])

  if test $glibcxx_cv_gets = yes; then
    AC_DEFINE(HAVE_GETS, 1, [Define if gets is available in <stdio.h> before C++14.])
  fi
  AC_MSG_RESULT($glibcxx_cv_gets)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check whether required C++11 overloads for floating point and integral
dnl types are present in <math.h>.
dnl
AC_DEFUN([GLIBCXX_CHECK_MATH11_PROTO], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -std=c++11"

  case "$host" in
    *-*-solaris2.*)
      # Solaris 12 Build 86, Solaris 11.3 SRU 3.6, and Solaris 10 Patch
      # 11996[67]-02 introduced the C++11 <math.h> floating point overloads.
      AC_MSG_CHECKING([for C++11 <math.h> floating point overloads])
      AC_CACHE_VAL(glibcxx_cv_math11_fp_overload, [
	AC_COMPILE_IFELSE([AC_LANG_SOURCE(
	  [#include <math.h>
	   #undef isfinite
	   namespace std {
	     inline bool isfinite(float __x)
	     { return __builtin_isfinite(__x); }
	   }
	])],
	[glibcxx_cv_math11_fp_overload=no],
	[glibcxx_cv_math11_fp_overload=yes]
      )])

      # autoheader cannot handle indented templates.
      AH_VERBATIM([__CORRECT_ISO_CPP11_MATH_H_PROTO_FP],
        [/* Define if all C++11 floating point overloads are available in <math.h>.  */
#if __cplusplus >= 201103L
#undef __CORRECT_ISO_CPP11_MATH_H_PROTO_FP
#endif])

      if test $glibcxx_cv_math11_fp_overload = yes; then
        AC_DEFINE(__CORRECT_ISO_CPP11_MATH_H_PROTO_FP)
      fi
      AC_MSG_RESULT([$glibcxx_cv_math11_fp_overload])

      # Solaris 12 Build 90, Solaris 11.3 SRU 5.6, and Solaris 10 Patch
      # 11996[67]-02 introduced the C++11 <math.h> integral type overloads.
      AC_MSG_CHECKING([for C++11 <math.h> integral type overloads])
      AC_CACHE_VAL(glibcxx_cv_math11_int_overload, [
	AC_COMPILE_IFELSE([AC_LANG_SOURCE(
	  [#include <math.h>
	   namespace std {
	     template<typename _Tp>
	       struct __is_integer;
	     template<>
	       struct __is_integer<int>
	       {
	         enum { __value = 1 };
	       };
	   }
	   namespace __gnu_cxx {
	     template<bool, typename>
	       struct __enable_if;
	     template<typename _Tp>
	       struct __enable_if<true, _Tp>
	       { typedef _Tp __type; };
	   }
	   namespace std {
	     template<typename _Tp>
	       constexpr typename __gnu_cxx::__enable_if
	       		 <__is_integer<_Tp>::__value, double>::__type
	       log2(_Tp __x)
	       { return __builtin_log2(__x); }
	   }
	   int
	   main (void)
	   {
	     int i = 1000;
	     return std::log2(i);
	   }
	])],
	[glibcxx_cv_math11_int_overload=no],
	[glibcxx_cv_math11_int_overload=yes]
      )])

      # autoheader cannot handle indented templates.
      AH_VERBATIM([__CORRECT_ISO_CPP11_MATH_H_PROTO_INT],
        [/* Define if all C++11 integral type overloads are available in <math.h>.  */
#if __cplusplus >= 201103L
#undef __CORRECT_ISO_CPP11_MATH_H_PROTO_INT
#endif])

      if test $glibcxx_cv_math11_int_overload = yes; then
        AC_DEFINE(__CORRECT_ISO_CPP11_MATH_H_PROTO_INT)
      fi
      AC_MSG_RESULT([$glibcxx_cv_math11_int_overload])
      ;;
    *)
      # If <math.h> defines the obsolete isinf(double) and isnan(double)
      # functions (instead of or as well as the C99 generic macros) then we
      # can't define std::isinf(double) and std::isnan(double) in <cmath>
      # and must use the ones from <math.h> instead.
      AC_MSG_CHECKING([for obsolete isinf function in <math.h>])
        AC_CACHE_VAL(glibcxx_cv_obsolete_isinf, [
          AC_COMPILE_IFELSE([AC_LANG_SOURCE(
            [#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
             #include <math.h>
             #undef isinf
             namespace std {
               using ::isinf;
               bool isinf(float);
               bool isinf(long double);
             }
             using std::isinf;
             bool b = isinf(0.0);
          ])],
          [glibcxx_cv_obsolete_isinf=yes],
          [glibcxx_cv_obsolete_isinf=no]
        )])
      AC_MSG_RESULT([$glibcxx_cv_obsolete_isinf])
      if test $glibcxx_cv_obsolete_isinf = yes; then
        AC_DEFINE(HAVE_OBSOLETE_ISINF, 1,
                  [Define if <math.h> defines obsolete isinf function.])
      fi

      AC_MSG_CHECKING([for obsolete isnan function in <math.h>])
        AC_CACHE_VAL(glibcxx_cv_obsolete_isnan, [
          AC_COMPILE_IFELSE([AC_LANG_SOURCE(
            [#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
             #include <math.h>
             #undef isnan
             namespace std {
               using ::isnan;
               bool isnan(float);
               bool isnan(long double);
             }
             using std::isnan;
             bool b = isnan(0.0);
          ])],
          [glibcxx_cv_obsolete_isnan=yes],
          [glibcxx_cv_obsolete_isnan=no]
        )])
      AC_MSG_RESULT([$glibcxx_cv_obsolete_isnan])
      if test $glibcxx_cv_obsolete_isnan = yes; then
        AC_DEFINE(HAVE_OBSOLETE_ISNAN, 1,
                  [Define if <math.h> defines obsolete isnan function.])
      fi
      ;;
  esac

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check for what type of C headers to use.
dnl
dnl --enable-cheaders= [does stuff].
dnl --disable-cheaders [does not do anything, really].
dnl  +  Usage:  GLIBCXX_ENABLE_CHEADERS[(DEFAULT)]
dnl       Where DEFAULT is either 'c' or 'c_std' or 'c_global'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CHEADERS], [
  GLIBCXX_ENABLE(cheaders,$1,[[[=KIND]]],
    [construct "C" headers for g++], [permit c|c_std|c_global])
  AC_MSG_NOTICE("C" header strategy set to $enable_cheaders)

  C_INCLUDE_DIR='${glibcxx_srcdir}/include/'$enable_cheaders

  # Allow overrides to configure.host here.
  if test $enable_cheaders = c_global; then
     c_compatibility=yes
  fi

  AC_SUBST(C_INCLUDE_DIR)
  GLIBCXX_CONDITIONAL(GLIBCXX_C_HEADERS_C, test $enable_cheaders = c)
  GLIBCXX_CONDITIONAL(GLIBCXX_C_HEADERS_C_STD, test $enable_cheaders = c_std)
  GLIBCXX_CONDITIONAL(GLIBCXX_C_HEADERS_C_GLOBAL, test $enable_cheaders = c_global)
  GLIBCXX_CONDITIONAL(GLIBCXX_C_HEADERS_COMPATIBILITY, test $c_compatibility = yes)
])


dnl
dnl Check for which locale library to use.  The choice is mapped to
dnl a subdirectory of config/locale.
dnl
dnl Default is generic.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CLOCALE], [
  GLIBCXX_ENABLE(clocale,auto,[[[=MODEL]]],
    [use MODEL for target locale package],
    [permit generic|gnu|ieee_1003.1-2001|newlib|yes|no|auto])

  # Deal with gettext issues.  Default to not using it (=no) until we detect
  # support for it later.  Let the user turn it off via --e/d, but let that
  # default to on for easier handling.
  USE_NLS=no
  AC_ARG_ENABLE(nls,
    AC_HELP_STRING([--enable-nls],[use Native Language Support (default)]),
    [],
    [enable_nls=yes])

  # Either a known package, or "auto"
  if test $enable_clocale = no || test $enable_clocale = yes; then
     enable_clocale=auto
  fi
  enable_clocale_flag=$enable_clocale

  # Probe for locale model to use if none specified.
  # Default to "generic".
  if test $enable_clocale_flag = auto; then
    case ${target_os} in
      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu)
	enable_clocale_flag=gnu
	;;
      darwin*)
	enable_clocale_flag=darwin
	;;
      dragonfly* | freebsd* | netbsd*)
	enable_clocale_flag=dragonfly
	;;
      openbsd*)
	enable_clocale_flag=newlib
	;;
      *)
	if test x"$with_newlib" = x"yes"; then
	  enable_clocale_flag=newlib
	else
	  enable_clocale_flag=generic
	fi
	;;
    esac
  fi

  # Sanity check model, and test for special functionality.
  if test $enable_clocale_flag = gnu; then
    AC_EGREP_CPP([_GLIBCXX_ok], [
    #include <features.h>
    #if (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3)) && !defined(__UCLIBC__)
      _GLIBCXX_ok
    #endif
    ], enable_clocale_flag=gnu, enable_clocale_flag=generic)

    # Set it to scream when it hurts.
    ac_save_CFLAGS="$CFLAGS"
    CFLAGS="-Wimplicit-function-declaration -Werror"

    # Use strxfrm_l if available.
    AC_TRY_COMPILE([#define _GNU_SOURCE 1
     		    #include <string.h>
		    #include <locale.h>],
		    [char s[128]; __locale_t loc; strxfrm_l(s, "C", 5, loc);],
		    AC_DEFINE(HAVE_STRXFRM_L, 1,
		    [Define if strxfrm_l is available in <string.h>.]),)

    # Use strerror_l if available.
    AC_TRY_COMPILE([#define _GNU_SOURCE 1
		    #include <string.h>
		    #include <locale.h>],
		    [__locale_t loc; strerror_l(5, loc);],
		    AC_DEFINE(HAVE_STRERROR_L, 1,
		    [Define if strerror_l is available in <string.h>.]),)

    CFLAGS="$ac_save_CFLAGS"
  fi

  # Perhaps use strerror_r if available, and strerror_l isn't.
  ac_save_CFLAGS="$CFLAGS"
  CFLAGS="-Wimplicit-function-declaration -Werror"
  AC_TRY_COMPILE([#define _GNU_SOURCE 1
	     	  #include <string.h>
		  #include <locale.h>],
		  [char s[128]; strerror_r(5, s, 128);],
		  AC_DEFINE(HAVE_STRERROR_R, 1,
		  [Define if strerror_r is available in <string.h>.]),)
  CFLAGS="$ac_save_CFLAGS"

  # Set configure bits for specified locale package
  AC_MSG_CHECKING([for C locale to use])
  case ${enable_clocale_flag} in
    generic)
      AC_MSG_RESULT(generic)

      CLOCALE_H=config/locale/generic/c_locale.h
      CLOCALE_CC=config/locale/generic/c_locale.cc
      CCODECVT_CC=config/locale/generic/codecvt_members.cc
      CCOLLATE_CC=config/locale/generic/collate_members.cc
      CCTYPE_CC=config/locale/generic/ctype_members.cc
      CMESSAGES_H=config/locale/generic/messages_members.h
      CMESSAGES_CC=config/locale/generic/messages_members.cc
      CMONEY_CC=config/locale/generic/monetary_members.cc
      CNUMERIC_CC=config/locale/generic/numeric_members.cc
      CTIME_H=config/locale/generic/time_members.h
      CTIME_CC=config/locale/generic/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
      ;;
    darwin)
      AC_MSG_RESULT(darwin)

      CLOCALE_H=config/locale/generic/c_locale.h
      CLOCALE_CC=config/locale/generic/c_locale.cc
      CCODECVT_CC=config/locale/generic/codecvt_members.cc
      CCOLLATE_CC=config/locale/generic/collate_members.cc
      CCTYPE_CC=config/locale/darwin/ctype_members.cc
      CMESSAGES_H=config/locale/generic/messages_members.h
      CMESSAGES_CC=config/locale/generic/messages_members.cc
      CMONEY_CC=config/locale/generic/monetary_members.cc
      CNUMERIC_CC=config/locale/generic/numeric_members.cc
      CTIME_H=config/locale/generic/time_members.h
      CTIME_CC=config/locale/generic/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
      ;;

    dragonfly)
      AC_MSG_RESULT(dragonfly or freebsd or netbsd)

      CLOCALE_H=config/locale/dragonfly/c_locale.h
      CLOCALE_CC=config/locale/dragonfly/c_locale.cc
      CCODECVT_CC=config/locale/dragonfly/codecvt_members.cc
      CCOLLATE_CC=config/locale/dragonfly/collate_members.cc
      CCTYPE_CC=config/locale/dragonfly/ctype_members.cc
      CMESSAGES_H=config/locale/generic/messages_members.h
      CMESSAGES_CC=config/locale/generic/messages_members.cc
      CMONEY_CC=config/locale/dragonfly/monetary_members.cc
      CNUMERIC_CC=config/locale/dragonfly/numeric_members.cc
      CTIME_H=config/locale/dragonfly/time_members.h
      CTIME_CC=config/locale/dragonfly/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
      ;;

    gnu)
      AC_MSG_RESULT(gnu)

      # Declare intention to use gettext, and add support for specific
      # languages.
      # For some reason, ALL_LINGUAS has to be before AM-GNU-GETTEXT
      ALL_LINGUAS="de fr"

      # Don't call AM-GNU-GETTEXT here. Instead, assume glibc.
      AC_CHECK_PROG(check_msgfmt, msgfmt, yes, no)
      if test x"$check_msgfmt" = x"yes" && test x"$enable_nls" = x"yes"; then
	USE_NLS=yes
      fi
      # Export the build objects.
      for ling in $ALL_LINGUAS; do \
	glibcxx_MOFILES="$glibcxx_MOFILES $ling.mo"; \
	glibcxx_POFILES="$glibcxx_POFILES $ling.po"; \
      done
      AC_SUBST(glibcxx_MOFILES)
      AC_SUBST(glibcxx_POFILES)

      CLOCALE_H=config/locale/gnu/c_locale.h
      CLOCALE_CC=config/locale/gnu/c_locale.cc
      CCODECVT_CC=config/locale/gnu/codecvt_members.cc
      CCOLLATE_CC=config/locale/gnu/collate_members.cc
      CCTYPE_CC=config/locale/gnu/ctype_members.cc
      CMESSAGES_H=config/locale/gnu/messages_members.h
      CMESSAGES_CC=config/locale/gnu/messages_members.cc
      CMONEY_CC=config/locale/gnu/monetary_members.cc
      CNUMERIC_CC=config/locale/gnu/numeric_members.cc
      CTIME_H=config/locale/gnu/time_members.h
      CTIME_CC=config/locale/gnu/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/gnu/c++locale_internal.h
      ;;
    ieee_1003.1-2001)
      AC_MSG_RESULT(IEEE 1003.1)

      CLOCALE_H=config/locale/ieee_1003.1-2001/c_locale.h
      CLOCALE_CC=config/locale/ieee_1003.1-2001/c_locale.cc
      CCODECVT_CC=config/locale/generic/codecvt_members.cc
      CCOLLATE_CC=config/locale/generic/collate_members.cc
      CCTYPE_CC=config/locale/generic/ctype_members.cc
      CMESSAGES_H=config/locale/ieee_1003.1-2001/messages_members.h
      CMESSAGES_CC=config/locale/ieee_1003.1-2001/messages_members.cc
      CMONEY_CC=config/locale/generic/monetary_members.cc
      CNUMERIC_CC=config/locale/generic/numeric_members.cc
      CTIME_H=config/locale/generic/time_members.h
      CTIME_CC=config/locale/generic/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
      ;;
    newlib)
      AC_MSG_RESULT(newlib)

      CLOCALE_H=config/locale/generic/c_locale.h
      CLOCALE_CC=config/locale/generic/c_locale.cc
      CCODECVT_CC=config/locale/generic/codecvt_members.cc
      CCOLLATE_CC=config/locale/generic/collate_members.cc
      CCTYPE_CC=config/locale/newlib/ctype_members.cc
      CMESSAGES_H=config/locale/generic/messages_members.h
      CMESSAGES_CC=config/locale/generic/messages_members.cc
      CMONEY_CC=config/locale/generic/monetary_members.cc
      CNUMERIC_CC=config/locale/generic/numeric_members.cc
      CTIME_H=config/locale/generic/time_members.h
      CTIME_CC=config/locale/generic/time_members.cc
      CLOCALE_INTERNAL_H=config/locale/generic/c++locale_internal.h
      ;;
  esac

  # This is where the testsuite looks for locale catalogs, using the
  # -DLOCALEDIR define during testsuite compilation.
  glibcxx_localedir=${glibcxx_builddir}/po/share/locale
  AC_SUBST(glibcxx_localedir)

  # A standalone libintl (e.g., GNU libintl) may be in use.
  if test $USE_NLS = yes; then
    AC_CHECK_HEADERS([libintl.h], [], USE_NLS=no)
    AC_SEARCH_LIBS(gettext, intl, [], USE_NLS=no)
  fi
  if test $USE_NLS = yes; then
    AC_DEFINE(_GLIBCXX_USE_NLS, 1,
	      [Define if NLS translations are to be used.])
  fi

  AC_SUBST(USE_NLS)
  AC_SUBST(CLOCALE_H)
  AC_SUBST(CMESSAGES_H)
  AC_SUBST(CCODECVT_CC)
  AC_SUBST(CCOLLATE_CC)
  AC_SUBST(CCTYPE_CC)
  AC_SUBST(CMESSAGES_CC)
  AC_SUBST(CMONEY_CC)
  AC_SUBST(CNUMERIC_CC)
  AC_SUBST(CTIME_H)
  AC_SUBST(CTIME_CC)
  AC_SUBST(CLOCALE_CC)
  AC_SUBST(CLOCALE_INTERNAL_H)
])


dnl
dnl Check for which std::allocator base class to use.  The choice is
dnl mapped from a subdirectory of include/ext.
dnl
dnl Default is new.
dnl
AC_DEFUN([GLIBCXX_ENABLE_ALLOCATOR], [
  AC_MSG_CHECKING([for std::allocator base class])
  GLIBCXX_ENABLE(libstdcxx-allocator,auto,[[[=KIND]]],
    [use KIND for target std::allocator base],
    [permit new|malloc|mt|bitmap|pool|yes|no|auto])

  # If they didn't use this option switch, or if they specified --enable
  # with no specific model, we'll have to look for one.  If they
  # specified --disable (???), do likewise.
  if test $enable_libstdcxx_allocator = no ||
     test $enable_libstdcxx_allocator = yes;
  then
     enable_libstdcxx_allocator=auto
  fi

  # Either a known package, or "auto". Auto implies the default choice
  # for a particular platform.
  enable_libstdcxx_allocator_flag=$enable_libstdcxx_allocator

  # Probe for host-specific support if no specific model is specified.
  # Default to "new".
  if test $enable_libstdcxx_allocator_flag = auto; then
    case ${target_os} in
      linux* | gnu* | kfreebsd*-gnu | knetbsd*-gnu)
	enable_libstdcxx_allocator_flag=new
	;;
      *)
	enable_libstdcxx_allocator_flag=new
	;;
    esac
  fi
  AC_MSG_RESULT($enable_libstdcxx_allocator_flag)


  # Set configure bits for specified locale package
  case ${enable_libstdcxx_allocator_flag} in
    bitmap)
      ALLOCATOR_H=config/allocator/bitmap_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::bitmap_allocator
      ;;
    malloc)
      ALLOCATOR_H=config/allocator/malloc_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::malloc_allocator
      ;;
    mt)
      ALLOCATOR_H=config/allocator/mt_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::__mt_alloc
      ;;
    new)
      ALLOCATOR_H=config/allocator/new_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::new_allocator
      ;;
    pool)
      ALLOCATOR_H=config/allocator/pool_allocator_base.h
      ALLOCATOR_NAME=__gnu_cxx::__pool_alloc
      ;;
  esac

  GLIBCXX_CONDITIONAL(ENABLE_ALLOCATOR_NEW,
		      test $enable_libstdcxx_allocator_flag = new)
  AC_SUBST(ALLOCATOR_H)
  AC_SUBST(ALLOCATOR_NAME)
])


dnl
dnl Check for whether the Boost-derived checks should be turned on.
dnl
dnl --enable-concept-checks turns them on.
dnl --disable-concept-checks leaves them off.
dnl  +  Usage:  GLIBCXX_ENABLE_CONCEPT_CHECKS[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CONCEPT_CHECKS], [
  GLIBCXX_ENABLE(concept-checks,$1,,[use Boost-derived template checks])
  if test $enable_concept_checks = yes; then
    AC_DEFINE(_GLIBCXX_CONCEPT_CHECKS, 1,
	      [Define to use concept checking code from the boost libraries.])
  fi
])

dnl
dnl Use extern templates.
dnl
dnl --enable-extern-template defines _GLIBCXX_EXTERN_TEMPLATE to 1
dnl --disable-extern-template defines _GLIBCXX_EXTERN_TEMPLATE to 0

dnl  +  Usage:  GLIBCXX_ENABLE_TEMPLATE[(DEFAULT)]
dnl       Where DEFAULT is `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_EXTERN_TEMPLATE], [

  GLIBCXX_ENABLE(extern-template,$1,,[enable extern template])

  AC_MSG_CHECKING([for extern template support])
  AC_MSG_RESULT([$enable_extern_template])

  GLIBCXX_CONDITIONAL(ENABLE_EXTERN_TEMPLATE, test $enable_extern_template = yes)
])

dnl
dnl Use vtable verification.
dnl
dnl --enable-vtable-verify defines _GLIBCXX_VTABLE_VERIFY to 1
dnl --disable-vtable-verify defines _GLIBCXX_VTABLE_VERIFY to 0

dnl  +  Usage:  GLIBCXX_ENABLE_VTABLE_VERIFY[(DEFAULT)]
dnl       Where DEFAULT is `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_VTABLE_VERIFY], [

  GLIBCXX_ENABLE(vtable-verify,$1,,[enable vtable verify])

  AC_MSG_CHECKING([for vtable verify support])
  AC_MSG_RESULT([$enable_vtable_verify])

  vtv_cygmin=no
  if test $enable_vtable_verify = yes; then
    case ${target_os} in
      cygwin*|mingw32*)
        VTV_CXXFLAGS="-fvtable-verify=std -Wl,-lvtv,-u_vtable_map_vars_start,-u_vtable_map_vars_end"
        VTV_CXXLINKFLAGS="-L${toplevel_builddir}/libvtv/.libs -Wl,--rpath -Wl,${toplevel_builddir}/libvtv/.libs"
        vtv_cygmin=yes
        ;;
      darwin*)
        VTV_CXXFLAGS="-fvtable-verify=std -Wl,-u,_vtable_map_vars_start -Wl,-u,_vtable_map_vars_end"
        VTV_CXXLINKFLAGS="-L${toplevel_builddir}/libvtv/.libs -Wl,-rpath,${toplevel_builddir}/libvtv/.libs"
        ;;
      solaris2*)
        VTV_CXXFLAGS="-fvtable-verify=std -Wl,-u_vtable_map_vars_start,-u_vtable_map_vars_end"
        VTV_CXXLINKFLAGS="-L${toplevel_builddir}/libvtv/.libs -Wl,-R -Wl,${toplevel_builddir}/libvtv/.libs"
        ;;
      *)
        VTV_CXXFLAGS="-fvtable-verify=std -Wl,-u_vtable_map_vars_start,-u_vtable_map_vars_end"
        VTV_CXXLINKFLAGS="-L${toplevel_builddir}/libvtv/.libs -Wl,--rpath -Wl,${toplevel_builddir}/libvtv/.libs"
        ;;
    esac
    VTV_PCH_CXXFLAGS="-fvtable-verify=std"
  else
    VTV_CXXFLAGS=
    VTV_PCH_CXXFLAGS=
    VTV_CXXLINKFLAGS=
  fi

  AC_SUBST(VTV_CXXFLAGS)
  AC_SUBST(VTV_PCH_CXXFLAGS)
  AC_SUBST(VTV_CXXLINKFLAGS)
  AM_CONDITIONAL(VTV_CYGMIN, test x$vtv_cygmin = xyes)
  GLIBCXX_CONDITIONAL(ENABLE_VTABLE_VERIFY, test $enable_vtable_verify = yes)
])

dnl
dnl Check for parallel mode pre-requisites, including OpenMP support.
dnl
dnl  +  Usage:  GLIBCXX_ENABLE_PARALLEL
dnl
AC_DEFUN([GLIBCXX_ENABLE_PARALLEL], [

  enable_parallel=no;

  # See if configured libgomp/omp.h exists. (libgomp may be in
  # noconfigdirs but not explicitly disabled.)
  if echo " ${TARGET_CONFIGDIRS} " | grep " libgomp " > /dev/null 2>&1 ; then
    enable_parallel=yes;
  else
    AC_MSG_NOTICE([target-libgomp not built])
  fi

  AC_MSG_CHECKING([for parallel mode support])
  AC_MSG_RESULT([$enable_parallel])
])


dnl
dnl Check for which I/O library to use:  stdio, or something specific.
dnl
dnl Default is stdio.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CSTDIO], [
  AC_MSG_CHECKING([for underlying I/O to use])
  GLIBCXX_ENABLE(cstdio,stdio,[[[=PACKAGE]]],
    [use target-specific I/O package], [permit stdio])

  # Now that libio has been removed, you can have any color you want as long
  # as it's black.  This is one big no-op until other packages are added, but
  # showing the framework never hurts.
  case ${enable_cstdio} in
    stdio)
      CSTDIO_H=config/io/c_io_stdio.h
      BASIC_FILE_H=config/io/basic_file_stdio.h
      BASIC_FILE_CC=config/io/basic_file_stdio.cc
      AC_MSG_RESULT(stdio)
      ;;
  esac

  AC_SUBST(CSTDIO_H)
  AC_SUBST(BASIC_FILE_H)
  AC_SUBST(BASIC_FILE_CC)
])


dnl
dnl Check for "unusual" flags to pass to the compiler while building.
dnl
dnl --enable-cxx-flags='-foo -bar -baz' is a general method for passing
dnl     experimental flags such as -fpch, -fIMI, -Dfloat=char, etc.
dnl --disable-cxx-flags passes nothing.
dnl  +  See http://gcc.gnu.org/ml/libstdc++/2000-q2/msg00131.html
dnl         http://gcc.gnu.org/ml/libstdc++/2000-q2/msg00284.html
dnl         http://gcc.gnu.org/ml/libstdc++/2000-q1/msg00035.html
dnl  +  Usage:  GLIBCXX_ENABLE_CXX_FLAGS(default flags)
dnl       If "default flags" is an empty string, the effect is the same
dnl       as --disable or --enable=no.
dnl
AC_DEFUN([GLIBCXX_ENABLE_CXX_FLAGS], [dnl
  AC_MSG_CHECKING([for extra compiler flags for building])
  GLIBCXX_ENABLE(cxx-flags,$1,[=FLAGS],
    [pass compiler FLAGS when building library],
    [case "x$enable_cxx_flags" in
      xno | x)   enable_cxx_flags= ;;
      x-*)       ;;
      *)         AC_MSG_ERROR(_g_switch needs compiler flags as arguments) ;;
     esac])

  # Run through flags (either default or command-line) and set anything
  # extra (e.g., #defines) that must accompany particular g++ options.
  if test -n "$enable_cxx_flags"; then
    for f in $enable_cxx_flags; do
      case "$f" in
	-fhonor-std)  ;;
	-*)  ;;
	*)   # and we're trying to pass /what/ exactly?
	     AC_MSG_ERROR([compiler flags start with a -]) ;;
      esac
    done
  fi

  EXTRA_CXX_FLAGS="$enable_cxx_flags"
  AC_MSG_RESULT($EXTRA_CXX_FLAGS)
  AC_SUBST(EXTRA_CXX_FLAGS)
])


dnl
dnl Check to see if debugging libraries are to be built.
dnl
dnl --enable-libstdcxx-debug
dnl builds a separate set of debugging libraries in addition to the
dnl normal (shared, static) libstdc++ binaries.
dnl
dnl --disable-libstdcxx-debug
dnl builds only one (non-debug) version of libstdc++.
dnl
dnl --enable-libstdcxx-debug-flags=FLAGS
dnl iff --enable-debug == yes, then use FLAGS to build the debug library.
dnl
dnl  +  Usage:  GLIBCXX_ENABLE_DEBUG[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_DEBUG], [
  AC_MSG_CHECKING([for additional debug build])
  skip_debug_build=
  GLIBCXX_ENABLE(libstdcxx-debug,$1,,[build extra debug library])
  if test x$enable_libstdcxx_debug = xyes; then
    if test -f $toplevel_builddir/../stage_final \
      && test -f $toplevel_builddir/../stage_current; then
      stage_final=`cat $toplevel_builddir/../stage_final`
      stage_current=`cat $toplevel_builddir/../stage_current`
      if test x$stage_current != x$stage_final ; then
	skip_debug_build=" (skipped for bootstrap stage $stage_current)"
	enable_libstdcxx_debug=no
      fi
    fi
  fi
  AC_MSG_RESULT($enable_libstdcxx_debug$skip_debug_build)
  GLIBCXX_CONDITIONAL(GLIBCXX_BUILD_DEBUG, test $enable_libstdcxx_debug = yes)
])


dnl
dnl Check for explicit debug flags.
dnl
dnl --enable-libstdcxx-debug-flags='-O1'
dnl is a general method for passing flags to be used when
dnl building debug libraries with --enable-libstdcxx-debug.
dnl
dnl --disable-libstdcxx-debug-flags does nothing.
dnl  +  Usage:  GLIBCXX_ENABLE_DEBUG_FLAGS(default flags)
dnl       If "default flags" is an empty string, the effect is the same
dnl       as --disable or --enable=no.
dnl
AC_DEFUN([GLIBCXX_ENABLE_DEBUG_FLAGS], [
  GLIBCXX_ENABLE(libstdcxx-debug-flags,[$1],[=FLAGS],
    [pass compiler FLAGS when building debug library],
    [case "x$enable_libstdcxx_debug_flags" in
      xno | x)    enable_libstdcxx_debug_flags= ;;
      x-*)        ;;
      *)          AC_MSG_ERROR(_g_switch needs compiler flags as arguments) ;;
     esac])

  # Option parsed, now set things appropriately
  DEBUG_FLAGS="$enable_libstdcxx_debug_flags"
  AC_SUBST(DEBUG_FLAGS)

  AC_MSG_NOTICE([Debug build flags set to $DEBUG_FLAGS])
])


dnl
dnl Check if the user only wants a freestanding library implementation.
dnl
dnl --disable-hosted-libstdcxx will turn off most of the library build,
dnl installing only the headers required by [17.4.1.3] and the language
dnl support library.  More than that will be built (to keep the Makefiles
dnl conveniently clean), but not installed.
dnl
dnl Sets:
dnl  is_hosted  (yes/no)
dnl
dnl Defines:
dnl  _GLIBCXX_HOSTED   (always defined, either to 1 or 0)
dnl
AC_DEFUN([GLIBCXX_ENABLE_HOSTED], [
  AC_ARG_ENABLE([hosted-libstdcxx],
    AC_HELP_STRING([--disable-hosted-libstdcxx],
		   [only build freestanding C++ runtime support]),,
    [case "$host" in
	arm*-*-symbianelf*)
	    enable_hosted_libstdcxx=no
	    ;;
	*)
	    enable_hosted_libstdcxx=yes
	    ;;
     esac])
  if test "$enable_hosted_libstdcxx" = no; then
    AC_MSG_NOTICE([Only freestanding libraries will be built])
    is_hosted=no
    hosted_define=0
    enable_abi_check=no
    enable_libstdcxx_pch=no
  else
    is_hosted=yes
    hosted_define=1
  fi
  GLIBCXX_CONDITIONAL(GLIBCXX_HOSTED, test $is_hosted = yes)
  AC_DEFINE_UNQUOTED(_GLIBCXX_HOSTED, $hosted_define,
    [Define to 1 if a full hosted library is built, or 0 if freestanding.])
])


dnl
dnl Check if the user wants a non-verbose library implementation.
dnl
dnl --disable-libstdcxx-verbose will turn off descriptive messages to
dnl standard error on termination.
dnl
dnl Defines:
dnl  _GLIBCXX_VERBOSE (always defined, either to 1 or 0)
dnl
AC_DEFUN([GLIBCXX_ENABLE_VERBOSE], [
  AC_ARG_ENABLE([libstdcxx-verbose],
    AC_HELP_STRING([--disable-libstdcxx-verbose],
		   [disable termination messages to standard error]),,
		   [enable_libstdcxx_verbose=yes])
  if test x"$enable_libstdcxx_verbose" = xyes; then
    verbose_define=1
  else
    AC_MSG_NOTICE([verbose termination messages are disabled])
    verbose_define=0
  fi
  AC_DEFINE_UNQUOTED(_GLIBCXX_VERBOSE, $verbose_define,
    [Define to 1 if a verbose library is built, or 0 otherwise.])
])


dnl
dnl Check for template specializations for the 'long long' type.
dnl The result determines only whether 'long long' I/O is enabled; things
dnl like numeric_limits<> specializations are always available.
dnl
dnl --enable-long-long defines _GLIBCXX_USE_LONG_LONG
dnl --disable-long-long leaves _GLIBCXX_USE_LONG_LONG undefined
dnl  +  Usage:  GLIBCXX_ENABLE_LONG_LONG[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_LONG_LONG], [
  GLIBCXX_ENABLE(long-long,$1,,[enable template specializations for 'long long'])
  if test $enable_long_long = yes; then
    AC_DEFINE(_GLIBCXX_USE_LONG_LONG, 1,
	      [Define if code specialized for long long should be used.])
  fi
  AC_MSG_CHECKING([for enabled long long specializations])
  AC_MSG_RESULT([$enable_long_long])
])


dnl
dnl Check for decimal floating point.
dnl See:
dnl http://gcc.gnu.org/onlinedocs/gcc/Decimal-Float.html#Decimal-Float
dnl
dnl This checks to see if the host supports decimal floating point types.
dnl
dnl Defines:
dnl  _GLIBCXX_USE_DECIMAL_FLOAT
dnl
AC_DEFUN([GLIBCXX_ENABLE_DECIMAL_FLOAT], [

  # Fake what AC_TRY_COMPILE does, without linking as this is
  # unnecessary for this test.

    cat > conftest.$ac_ext << EOF
[#]line __oline__ "configure"
int main()
{
  _Decimal32 d1;
  _Decimal64 d2;
  _Decimal128 d3;
  return 0;
}
EOF

    AC_MSG_CHECKING([for ISO/IEC TR 24733 ])
    if AC_TRY_EVAL(ac_compile); then
      AC_DEFINE(_GLIBCXX_USE_DECIMAL_FLOAT, 1,
      [Define if ISO/IEC TR 24733 decimal floating point types are supported on this host.])
      enable_dfp=yes
    else
      enable_dfp=no
    fi
    AC_MSG_RESULT($enable_dfp)
    rm -f conftest*
])

dnl
dnl Check for GNU 128-bit integer and floating point types.
dnl
dnl Note: also checks that the types aren't standard types.
dnl
dnl Defines:
dnl  _GLIBCXX_USE_INT128
dnl  ENABLE_FLOAT128
dnl
AC_DEFUN([GLIBCXX_ENABLE_INT128_FLOAT128], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS

  # Fake what AC_TRY_COMPILE does, without linking as this is
  # unnecessary for this test.

    cat > conftest.$ac_ext << EOF
[#]line __oline__ "configure"
template<typename T1, typename T2>
  struct same
  { typedef T2 type; };

template<typename T>
  struct same<T, T>;

int main()
{
  typename same<long, __int128>::type                i1;
  typename same<long long, __int128>::type           i2;
}
EOF

    AC_MSG_CHECKING([for __int128])
    if AC_TRY_EVAL(ac_compile); then
      AC_DEFINE(_GLIBCXX_USE_INT128, 1,
      [Define if __int128 is supported on this host.])
      enable_int128=yes
    else
      enable_int128=no
    fi
    AC_MSG_RESULT($enable_int128)
    rm -f conftest*

    cat > conftest.$ac_ext << EOF
[#]line __oline__ "configure"
template<typename T1, typename T2>
  struct same
  { typedef T2 type; };

template<typename T>
  struct same<T, T>;

int main()
{
  typename same<double, __float128>::type      f1;
  typename same<long double, __float128>::type f2;
}
EOF

    AC_MSG_CHECKING([for __float128])
    if AC_TRY_EVAL(ac_compile); then
      enable_float128=yes
    else
      enable_float128=no
    fi
    AC_MSG_RESULT($enable_float128)
    GLIBCXX_CONDITIONAL(ENABLE_FLOAT128, test $enable_float128 = yes)
    rm -f conftest*

  AC_LANG_RESTORE
])

dnl
dnl Check for template specializations for the 'wchar_t' type.
dnl
dnl --enable-wchar_t defines _GLIBCXX_USE_WCHAR_T
dnl --disable-wchar_t leaves _GLIBCXX_USE_WCHAR_T undefined
dnl  +  Usage:  GLIBCXX_ENABLE_WCHAR_T[(DEFAULT)]
dnl       Where DEFAULT is either `yes' or `no'.
dnl
dnl Necessary support must also be present.
dnl
AC_DEFUN([GLIBCXX_ENABLE_WCHAR_T], [
  GLIBCXX_ENABLE(wchar_t,$1,,[enable template specializations for 'wchar_t'])

  # Test wchar.h for mbstate_t, which is needed for char_traits and fpos.
  AC_CHECK_HEADERS(wchar.h, ac_has_wchar_h=yes, ac_has_wchar_h=no)
  AC_MSG_CHECKING([for mbstate_t])
  AC_TRY_COMPILE([#include <wchar.h>],
  [mbstate_t teststate;],
  have_mbstate_t=yes, have_mbstate_t=no)
  AC_MSG_RESULT($have_mbstate_t)
  if test x"$have_mbstate_t" = xyes; then
    AC_DEFINE(HAVE_MBSTATE_T,1,[Define if mbstate_t exists in wchar.h.])
  fi

  # Test it always, for use in GLIBCXX_ENABLE_C99, together with
  # ac_has_wchar_h.
  AC_CHECK_HEADERS(wctype.h, ac_has_wctype_h=yes, ac_has_wctype_h=no)

  if test x"$enable_wchar_t" = x"yes"; then

    AC_LANG_SAVE
    AC_LANG_CPLUSPLUS

    if test x"$ac_has_wchar_h" = xyes &&
       test x"$ac_has_wctype_h" = xyes; then
      AC_TRY_COMPILE([#include <wchar.h>
		      #include <stddef.h>
		      wint_t i;
		      long l = WEOF;
		      long j = WCHAR_MIN;
		      long k = WCHAR_MAX;
		      namespace test
		      {
			using ::btowc;
			using ::fgetwc;
			using ::fgetws;
			using ::fputwc;
			using ::fputws;
			using ::fwide;
			using ::fwprintf;
			using ::fwscanf;
			using ::getwc;
			using ::getwchar;
 			using ::mbrlen;
			using ::mbrtowc;
			using ::mbsinit;
			using ::mbsrtowcs;
			using ::putwc;
			using ::putwchar;
			using ::swprintf;
			using ::swscanf;
			using ::ungetwc;
			using ::vfwprintf;
			using ::vswprintf;
			using ::vwprintf;
			using ::wcrtomb;
			using ::wcscat;
			using ::wcschr;
			using ::wcscmp;
			using ::wcscoll;
			using ::wcscpy;
			using ::wcscspn;
			using ::wcsftime;
			using ::wcslen;
			using ::wcsncat;
			using ::wcsncmp;
			using ::wcsncpy;
			using ::wcspbrk;
			using ::wcsrchr;
			using ::wcsrtombs;
			using ::wcsspn;
			using ::wcsstr;
			using ::wcstod;
			using ::wcstok;
			using ::wcstol;
			using ::wcstoul;
			using ::wcsxfrm;
			using ::wctob;
			using ::wmemchr;
			using ::wmemcmp;
			using ::wmemcpy;
			using ::wmemmove;
			using ::wmemset;
			using ::wprintf;
			using ::wscanf;
		      }
		     ],[],[], [enable_wchar_t=no])
    else
      enable_wchar_t=no
    fi

    AC_LANG_RESTORE
  fi

  if test x"$enable_wchar_t" = x"yes"; then
    AC_DEFINE(_GLIBCXX_USE_WCHAR_T, 1,
	      [Define if code specialized for wchar_t should be used.])
  fi

  AC_MSG_CHECKING([for enabled wchar_t specializations])
  AC_MSG_RESULT([$enable_wchar_t])
])


dnl
dnl Check to see if building and using a C++ precompiled header can be done.
dnl
dnl --enable-libstdcxx-pch=yes
dnl default, this shows intent to use stdc++.h.gch If it looks like it
dnl may work, after some light-hearted attempts to puzzle out compiler
dnl support, flip bits on in include/Makefile.am
dnl
dnl --disable-libstdcxx-pch
dnl turns off attempts to use or build stdc++.h.gch.
dnl
dnl Substs:
dnl  glibcxx_PCHFLAGS
dnl
AC_DEFUN([GLIBCXX_ENABLE_PCH], [
  GLIBCXX_ENABLE(libstdcxx-pch,$1,,[build pre-compiled libstdc++ headers])
  if test $enable_libstdcxx_pch = yes; then
    AC_CACHE_CHECK([for compiler with PCH support],
      [glibcxx_cv_prog_CXX_pch],
      [ac_save_CXXFLAGS="$CXXFLAGS"
       CXXFLAGS="$CXXFLAGS -Werror -Winvalid-pch -Wno-deprecated"
       AC_LANG_SAVE
       AC_LANG_CPLUSPLUS
       echo '#include <math.h>' > conftest.h
       if $CXX $CXXFLAGS $CPPFLAGS -x c++-header conftest.h \
			  -o conftest.h.gch 1>&5 2>&1 &&
		echo '#error "pch failed"' > conftest.h &&
	  echo '#include "conftest.h"' > conftest.cc &&
	       $CXX -c $CXXFLAGS $CPPFLAGS conftest.cc 1>&5 2>&1 ;
       then
	 glibcxx_cv_prog_CXX_pch=yes
       else
	 glibcxx_cv_prog_CXX_pch=no
       fi
       rm -f conftest*
       CXXFLAGS=$ac_save_CXXFLAGS
       AC_LANG_RESTORE
      ])
    enable_libstdcxx_pch=$glibcxx_cv_prog_CXX_pch
  fi

  AC_MSG_CHECKING([for enabled PCH])
  AC_MSG_RESULT([$enable_libstdcxx_pch])

  GLIBCXX_CONDITIONAL(GLIBCXX_BUILD_PCH, test $enable_libstdcxx_pch = yes)
  if test $enable_libstdcxx_pch = yes; then
    glibcxx_PCHFLAGS="-include bits/stdc++.h"
  else
    glibcxx_PCHFLAGS=""
  fi
  AC_SUBST(glibcxx_PCHFLAGS)
])


dnl
dnl Check for atomic builtins.
dnl See:
dnl http://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html
dnl
dnl This checks to see if the host supports the compiler-generated
dnl builtins for atomic operations for various integral sizes. Note, this
dnl is intended to be an all-or-nothing switch, so all the atomic operations
dnl that are used should be checked.
dnl
dnl Note:
dnl libgomp and libgfortran use a link test, see CHECK_SYNC_FETCH_AND_ADD.
dnl
AC_DEFUN([GLIBCXX_ENABLE_ATOMIC_BUILTINS], [
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  old_CXXFLAGS="$CXXFLAGS"

  # Do link tests if possible, instead asm tests, limited to some platforms
  # see discussion in PR target/40134, PR libstdc++/40133 and the thread
  # starting at http://gcc.gnu.org/ml/gcc-patches/2009-07/msg00322.html
  atomic_builtins_link_tests=no
  if test x$gcc_no_link != xyes; then
    # Can do link tests. Limit to some tested platforms
    case "$host" in
      *-*-linux* | *-*-uclinux* | *-*-kfreebsd*-gnu | *-*-gnu*)
	atomic_builtins_link_tests=yes
	;;
    esac
  fi

  if test x$atomic_builtins_link_tests = xyes; then

  # Do link tests.

  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  AC_MSG_CHECKING([for atomic builtins for bool])
  AC_CACHE_VAL(glibcxx_cv_atomic_bool, [
    AC_TRY_LINK(
      [ ],
      [typedef bool atomic_type;
       atomic_type c1;
       atomic_type c2;
       atomic_type c3(0);
       // N.B. __atomic_fetch_add is not supported for bool.
       __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL,
				   __ATOMIC_RELAXED);
       __atomic_test_and_set(&c1, __ATOMIC_RELAXED);
       __atomic_load_n(&c1, __ATOMIC_RELAXED);
      ],
      [glibcxx_cv_atomic_bool=yes],
      [glibcxx_cv_atomic_bool=no])
  ])
  AC_MSG_RESULT($glibcxx_cv_atomic_bool)

  AC_MSG_CHECKING([for atomic builtins for short])
  AC_CACHE_VAL(glibcxx_cv_atomic_short, [
    AC_TRY_LINK(
      [ ],
      [typedef short atomic_type;
       atomic_type c1;
       atomic_type c2;
       atomic_type c3(0);
       __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED);
       __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL,
				   __ATOMIC_RELAXED);
       __atomic_test_and_set(&c1, __ATOMIC_RELAXED);
       __atomic_load_n(&c1, __ATOMIC_RELAXED);
      ],
      [glibcxx_cv_atomic_short=yes],
      [glibcxx_cv_atomic_short=no])
  ])
  AC_MSG_RESULT($glibcxx_cv_atomic_short)

  AC_MSG_CHECKING([for atomic builtins for int])
  AC_CACHE_VAL(glibcxx_cv_atomic_int, [
    AC_TRY_LINK(
      [ ],
      [typedef int atomic_type;
       atomic_type c1;
       atomic_type c2;
       atomic_type c3(0);
       __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED);
       __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL,
				   __ATOMIC_RELAXED);
       __atomic_test_and_set(&c1, __ATOMIC_RELAXED);
       __atomic_load_n(&c1, __ATOMIC_RELAXED);
      ],
      [glibcxx_cv_atomic_int=yes],
      [glibcxx_cv_atomic_int=no])
  ])
  AC_MSG_RESULT($glibcxx_cv_atomic_int)

  AC_MSG_CHECKING([for atomic builtins for long long])
  AC_CACHE_VAL(glibcxx_cv_atomic_long_long, [
    AC_TRY_LINK(
      [ ],
      [typedef long long atomic_type;
       atomic_type c1;
       atomic_type c2;
       atomic_type c3(0);
       __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED);
       __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL,
				   __ATOMIC_RELAXED);
       __atomic_test_and_set(&c1, __ATOMIC_RELAXED);
       __atomic_load_n(&c1, __ATOMIC_RELAXED);
      ],
      [glibcxx_cv_atomic_long_long=yes],
      [glibcxx_cv_atomic_long_long=no])
  ])
  AC_MSG_RESULT($glibcxx_cv_atomic_long_long)

  else

  # Do asm tests.

  # Compile unoptimized.
  CXXFLAGS='-O0 -S'

  # Fake what AC_TRY_COMPILE does.

    cat > conftest.$ac_ext << EOF
[#]line __oline__ "configure"
int main()
{
  typedef bool atomic_type;
  atomic_type c1;
  atomic_type c2;
  atomic_type c3(0);
  // N.B. __atomic_fetch_add is not supported for bool.
  __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL,
			      __ATOMIC_RELAXED);
  __atomic_test_and_set(&c1, __ATOMIC_RELAXED);
  __atomic_load_n(&c1, __ATOMIC_RELAXED);

  return 0;
}
EOF

    AC_MSG_CHECKING([for atomic builtins for bool])
    if AC_TRY_EVAL(ac_compile); then
      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
	glibcxx_cv_atomic_bool=no
      else
	glibcxx_cv_atomic_bool=yes
      fi
    fi
    AC_MSG_RESULT($glibcxx_cv_atomic_bool)
    rm -f conftest*

    cat > conftest.$ac_ext << EOF
[#]line __oline__ "configure"
int main()
{
  typedef short atomic_type;
  atomic_type c1;
  atomic_type c2;
  atomic_type c3(0);
  __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED);
  __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL,
			      __ATOMIC_RELAXED);
  __atomic_test_and_set(&c1, __ATOMIC_RELAXED);
  __atomic_load_n(&c1, __ATOMIC_RELAXED);

  return 0;
}
EOF

    AC_MSG_CHECKING([for atomic builtins for short])
    if AC_TRY_EVAL(ac_compile); then
      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
	glibcxx_cv_atomic_short=no
      else
	glibcxx_cv_atomic_short=yes
      fi
    fi
    AC_MSG_RESULT($glibcxx_cv_atomic_short)
    rm -f conftest*

    cat > conftest.$ac_ext << EOF
[#]line __oline__ "configure"
int main()
{
  // NB: _Atomic_word not necessarily int.
  typedef int atomic_type;
  atomic_type c1;
  atomic_type c2;
  atomic_type c3(0);
  __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED);
  __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL,
			      __ATOMIC_RELAXED);
  __atomic_test_and_set(&c1, __ATOMIC_RELAXED);
  __atomic_load_n(&c1, __ATOMIC_RELAXED);

  return 0;
}
EOF

    AC_MSG_CHECKING([for atomic builtins for int])
    if AC_TRY_EVAL(ac_compile); then
      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
	glibcxx_cv_atomic_int=no
      else
	glibcxx_cv_atomic_int=yes
      fi
    fi
    AC_MSG_RESULT($glibcxx_cv_atomic_int)
    rm -f conftest*

    cat > conftest.$ac_ext << EOF
[#]line __oline__ "configure"
int main()
{
  typedef long long atomic_type;
  atomic_type c1;
  atomic_type c2;
  atomic_type c3(0);
  __atomic_fetch_add(&c1, c2, __ATOMIC_RELAXED);
  __atomic_compare_exchange_n(&c1, &c2, c3, true, __ATOMIC_ACQ_REL,
			      __ATOMIC_RELAXED);
  __atomic_test_and_set(&c1, __ATOMIC_RELAXED);
  __atomic_load_n(&c1, __ATOMIC_RELAXED);

  return 0;
}
EOF

    AC_MSG_CHECKING([for atomic builtins for long long])
    if AC_TRY_EVAL(ac_compile); then
      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
	glibcxx_cv_atomic_long_long=no
      else
	glibcxx_cv_atomic_long_long=yes
      fi
    fi
    AC_MSG_RESULT($glibcxx_cv_atomic_long_long)
    rm -f conftest*

  fi

  CXXFLAGS="$old_CXXFLAGS"
  AC_LANG_RESTORE

  # Set atomicity_dir to builtins if all but the long long test above passes,
  # or if the builtins were already chosen (e.g. by configure.host).
  if { test "$glibcxx_cv_atomic_bool" = yes \
     && test "$glibcxx_cv_atomic_short" = yes \
     && test "$glibcxx_cv_atomic_int" = yes; } \
     || test "$atomicity_dir" = "cpu/generic/atomicity_builtins"; then
    AC_DEFINE(_GLIBCXX_ATOMIC_BUILTINS, 1,
    [Define if the compiler supports C++11 atomics.])
    atomicity_dir=cpu/generic/atomicity_builtins
  fi

  # If still generic, set to mutex.
  if test $atomicity_dir = "cpu/generic" ; then
    atomicity_dir=cpu/generic/atomicity_mutex
    AC_MSG_WARN([No native atomic operations are provided for this platform.])
      if test "x$target_thread_file" = xsingle; then
	AC_MSG_WARN([They cannot be faked when thread support is disabled.])
	AC_MSG_WARN([Thread-safety of certain classes is not guaranteed.])
      else
	AC_MSG_WARN([They will be faked using a mutex.])
	AC_MSG_WARN([Performance of certain classes will degrade as a result.])
      fi
  fi

])

dnl
dnl Set default lock policy for synchronizing shared_ptr reference counting.
dnl
dnl --with-libstdcxx-lock-policy=auto
dnl	Use atomic operations for shared_ptr reference counting only if
dnl	the default target supports atomic compare-and-swap.
dnl --with-libstdcxx-lock-policy=atomic
dnl	Use atomic operations for shared_ptr reference counting.
dnl --with-libstdcxx-lock-policy=mutex
dnl	Use a mutex to synchronize shared_ptr reference counting.
dnl
dnl This controls the value of __gnu_cxx::__default_lock_policy, which
dnl determines how shared_ptr reference counts are synchronized.
dnl The option "atomic" means that atomic operations should be used,
dnl "mutex" means that a mutex will be used. The default option, "auto",
dnl will check if the target supports the compiler-generated builtins
dnl for atomic compare-and-swap operations for 2-byte and 4-byte integers,
dnl and will use "atomic" if supported, "mutex" otherwise.
dnl This option is ignored if the thread model used by GCC is "single",
dnl as no synchronization is used at all in that case.
dnl This option affects the library ABI (except in the "single" thread model).
dnl
dnl Defines _GLIBCXX_HAVE_ATOMIC_LOCK_POLICY to 1 if atomics should be used.
dnl
AC_DEFUN([GLIBCXX_ENABLE_LOCK_POLICY], [

  AC_ARG_WITH([libstdcxx-lock-policy],
    AC_HELP_STRING([--with-libstdcxx-lock-policy={atomic,mutex,auto}],
      [synchronization policy for shared_ptr reference counting [default=auto]]),
              [libstdcxx_atomic_lock_policy=$withval],
              [libstdcxx_atomic_lock_policy=auto])

  case "$libstdcxx_atomic_lock_policy" in
    atomic|mutex|auto) ;;
    *) AC_MSG_ERROR([Invalid argument for --with-libstdcxx-lock-policy]) ;;
  esac
  AC_MSG_CHECKING([for lock policy for shared_ptr reference counts])

  if test x"$libstdcxx_atomic_lock_policy" = x"auto"; then
    AC_LANG_SAVE
    AC_LANG_CPLUSPLUS
    ac_save_CXXFLAGS="$CXXFLAGS"

    dnl Why do we care about 2-byte CAS on targets with 4-byte _Atomic_word?!
    AC_TRY_COMPILE([
    #if ! defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2
    # error "No 2-byte compare-and-swap"
    #elif ! defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
    # error "No 4-byte compare-and-swap"
    #endif
    ],,
    [libstdcxx_atomic_lock_policy=atomic],
    [libstdcxx_atomic_lock_policy=mutex])
    AC_LANG_RESTORE
    CXXFLAGS="$ac_save_CXXFLAGS"
  fi

  if test x"$libstdcxx_atomic_lock_policy" = x"atomic"; then
    AC_MSG_RESULT(atomic)
    AC_DEFINE(HAVE_ATOMIC_LOCK_POLICY,1,
      [Defined if shared_ptr reference counting should use atomic operations.])
  else
    AC_MSG_RESULT(mutex)
  fi

])

dnl
dnl Allow visibility attributes to be used on namespaces, objects, etc.
dnl
dnl --enable-libstdcxx-visibility enables attempt to use visibility attributes.
dnl --disable-libstdcxx-visibility turns off all use of visibility attributes.
dnl  +  Usage:  GLIBCXX_ENABLE_LIBSTDCXX_VISIBILITY[(DEFAULT)]
dnl       Where DEFAULT is 'yes'.
dnl
AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_VISIBILITY], [
GLIBCXX_ENABLE(libstdcxx-visibility,$1,,[enables visibility safe usage])

if test x$enable_libstdcxx_visibility = xyes ; then
  dnl all hail libgfortran
  dnl Check whether the target supports hidden visibility.
  AC_CACHE_CHECK([whether the target supports hidden visibility],
		 glibcxx_cv_have_attribute_visibility, [
  save_CFLAGS="$CFLAGS"
  CFLAGS="$CFLAGS -Werror"
  AC_TRY_COMPILE([void __attribute__((visibility("hidden"))) foo(void) { }],
		 [], glibcxx_cv_have_attribute_visibility=yes,
		 glibcxx_cv_have_attribute_visibility=no)
  CFLAGS="$save_CFLAGS"])
  if test $glibcxx_cv_have_attribute_visibility = no; then
    enable_libstdcxx_visibility=no
  fi
fi

GLIBCXX_CONDITIONAL(ENABLE_VISIBILITY, test $enable_libstdcxx_visibility = yes)
AC_MSG_NOTICE([visibility supported: $enable_libstdcxx_visibility])
])


dnl
dnl Add version tags to symbols in shared library (or not), additionally
dnl marking other symbols as private/local (or not).
dnl
dnl Sets libtool_VERSION, and determines shared library SONAME.
dnl
dnl  This depends on GLIBCXX CHECK_LINKER_FEATURES, but without it assumes no.
dnl
dnl --enable-symvers=style adds a version script to the linker call when
dnl       creating the shared library.  The choice of version script is
dnl       controlled by 'style'.
dnl --disable-symvers does not.
dnl
dnl  +  Usage:  GLIBCXX_ENABLE_SYMVERS[(DEFAULT)]
dnl       Where DEFAULT is either 'yes' or 'no'.  Passing `yes' tries to
dnl       choose a default style based on linker characteristics.  Passing
dnl       'no' disables versioning.
dnl
AC_DEFUN([GLIBCXX_ENABLE_SYMVERS], [

GLIBCXX_ENABLE(symvers,$1,[[[=STYLE]]],
  [enables symbol versioning of the shared library],
  [permit yes|no|gnu|gnu-versioned-namespace|darwin|darwin-export|sun])

# If we never went through the GLIBCXX_CHECK_LINKER_FEATURES macro, then we
# don't know enough about $LD to do tricks...
AC_REQUIRE([GLIBCXX_CHECK_LINKER_FEATURES])
# Sun style symbol versions needs GNU c++filt for make_sunver.pl to work
# with extern "C++" in version scripts.
AC_REQUIRE([GCC_PROG_GNU_CXXFILT])

# Turn a 'yes' into a suitable default.
if test x$enable_symvers = xyes ; then
  if test $enable_shared = no || test "x$LD" = x || test x$gcc_no_link = xyes; then
    enable_symvers=no
  else
    if test $with_gnu_ld = yes ; then
      case ${target_os} in
	hpux*)
	  enable_symvers=no ;;
	*)
	  enable_symvers=gnu ;;
      esac
    else
      case ${target_os} in
	darwin*)
	  enable_symvers=darwin ;;
	# Sun symbol versioning exists since Solaris 2.5.
	solaris2.[[5-9]]* | solaris2.1[[0-9]]*)
	  # make_sunver.pl needs GNU c++filt to support extern "C++" in
	  # version scripts, so disable symbol versioning if none can be
	  # found.
	  if test -z "$ac_cv_path_CXXFILT"; then
	    AC_MSG_WARN([=== You have requested Sun symbol versioning, but])
	    AC_MSG_WARN([=== no GNU c++filt could  be found.])
	    AC_MSG_WARN([=== Symbol versioning will be disabled.])
	    enable_symvers=no
	  else
	    enable_symvers=sun
	  fi
	  ;;
	*)
	  enable_symvers=no ;;
      esac
    fi
  fi
fi

# Check to see if 'darwin' or 'darwin-export' can win.
if test x$enable_symvers = xdarwin-export ; then
    enable_symvers=darwin
fi

# Check if 'sun' was requested on non-Solaris 2 platforms.
if test x$enable_symvers = xsun ; then
  case ${target_os} in
    solaris2*)
      # All fine.
      ;;
    *)
      # Unlikely to work.
      AC_MSG_WARN([=== You have requested Sun symbol versioning, but])
      AC_MSG_WARN([=== you are not targetting Solaris 2.])
      AC_MSG_WARN([=== Symbol versioning will be disabled.])
      enable_symvers=no
      ;;
  esac
fi

# Check to see if 'gnu' can win.
if test $enable_symvers = gnu ||
  test $enable_symvers = gnu-versioned-namespace ||
  test $enable_symvers = sun; then
  # Check to see if libgcc_s exists, indicating that shared libgcc is possible.
  AC_MSG_CHECKING([for shared libgcc])
  ac_save_CFLAGS="$CFLAGS"
  CFLAGS=' -lgcc_s'
  AC_TRY_LINK(, [return 0;], glibcxx_shared_libgcc=yes, glibcxx_shared_libgcc=no)
  CFLAGS="$ac_save_CFLAGS"
  if test $glibcxx_shared_libgcc = no; then
    cat > conftest.c <<EOF
int main (void) { return 0; }
EOF
changequote(,)dnl
    glibcxx_libgcc_s_suffix=`${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
			     -shared -shared-libgcc -o conftest.so \
			     conftest.c -v 2>&1 >/dev/null \
			     | sed -n 's/^.* -lgcc_s\([^ ]*\) .*$/\1/p'`
changequote([,])dnl
    rm -f conftest.c conftest.so
    if test x${glibcxx_libgcc_s_suffix+set} = xset; then
      CFLAGS=" -lgcc_s$glibcxx_libgcc_s_suffix"
      AC_TRY_LINK(, [return 0;], glibcxx_shared_libgcc=yes)
      CFLAGS="$ac_save_CFLAGS"
    fi
  fi
  AC_MSG_RESULT($glibcxx_shared_libgcc)

  # For GNU ld, we need at least this version.  The format is described in
  # GLIBCXX_CHECK_LINKER_FEATURES above.
  glibcxx_min_gnu_ld_version=21400

  # If no shared libgcc, can't win.
  if test $glibcxx_shared_libgcc != yes; then
      AC_MSG_WARN([=== You have requested GNU symbol versioning, but])
      AC_MSG_WARN([=== you are not building a shared libgcc_s.])
      AC_MSG_WARN([=== Symbol versioning will be disabled.])
      enable_symvers=no
  elif test $with_gnu_ld != yes && test $enable_symvers = sun; then
    : All interesting versions of Sun ld support sun style symbol versioning.
  elif test $with_gnu_ld != yes ; then
    # just fail for now
    AC_MSG_WARN([=== You have requested GNU symbol versioning, but])
    AC_MSG_WARN([=== you are not using the GNU linker.])
    AC_MSG_WARN([=== Symbol versioning will be disabled.])
    enable_symvers=no
  elif test $glibcxx_ld_is_gold = yes ; then
    : All versions of gold support symbol versioning.
  elif test $glibcxx_gnu_ld_version -lt $glibcxx_min_gnu_ld_version ; then
    # The right tools, the right setup, but too old.  Fallbacks?
    AC_MSG_WARN(=== Linker version $glibcxx_gnu_ld_version is too old for)
    AC_MSG_WARN(=== full symbol versioning support in this release of GCC.)
    AC_MSG_WARN(=== You would need to upgrade your binutils to version)
    AC_MSG_WARN(=== $glibcxx_min_gnu_ld_version or later and rebuild GCC.)
    AC_MSG_WARN([=== Symbol versioning will be disabled.])
    enable_symvers=no
  fi
fi

# For libtool versioning info, format is CURRENT:REVISION:AGE
libtool_VERSION=6:28:0

# Everything parsed; figure out what files and settings to use.
case $enable_symvers in
  no)
    SYMVER_FILE=config/abi/pre/none.ver
    ;;
  gnu)
    SYMVER_FILE=config/abi/pre/gnu.ver
    AC_DEFINE(_GLIBCXX_SYMVER_GNU, 1,
	      [Define to use GNU versioning in the shared library.])
    ;;
  gnu-versioned-namespace)
    libtool_VERSION=8:0:0
    SYMVER_FILE=config/abi/pre/gnu-versioned-namespace.ver
    AC_DEFINE(_GLIBCXX_SYMVER_GNU_NAMESPACE, 1,
	      [Define to use GNU namespace versioning in the shared library.])
    ;;
  darwin)
    SYMVER_FILE=config/abi/pre/gnu.ver
    AC_DEFINE(_GLIBCXX_SYMVER_DARWIN, 1,
	      [Define to use darwin versioning in the shared library.])
    ;;
  sun)
    SYMVER_FILE=config/abi/pre/gnu.ver
    AC_DEFINE(_GLIBCXX_SYMVER_SUN, 1,
	      [Define to use Sun versioning in the shared library.])
    ;;
esac

if test x$enable_symvers != xno ; then
  AC_DEFINE(_GLIBCXX_SYMVER, 1,
	 [Define to use symbol versioning in the shared library.])
fi

AC_CACHE_CHECK([whether the target supports .symver directive],
	       glibcxx_cv_have_as_symver_directive, [
  AC_TRY_COMPILE([void foo (void); __asm (".symver foo, bar@SYMVER");],
		 [], glibcxx_cv_have_as_symver_directive=yes,
		 glibcxx_cv_have_as_symver_directive=no)])
if test $glibcxx_cv_have_as_symver_directive = yes; then
  AC_DEFINE(HAVE_AS_SYMVER_DIRECTIVE, 1,
    [Define to 1 if the target assembler supports .symver directive.])
fi

AC_SUBST(SYMVER_FILE)
AC_SUBST(port_specific_symbol_files)
GLIBCXX_CONDITIONAL(ENABLE_SYMVERS, test $enable_symvers != no)
GLIBCXX_CONDITIONAL(ENABLE_SYMVERS_GNU, test $enable_symvers = gnu)
GLIBCXX_CONDITIONAL(ENABLE_SYMVERS_GNU_NAMESPACE, test $enable_symvers = gnu-versioned-namespace)
GLIBCXX_CONDITIONAL(ENABLE_SYMVERS_DARWIN, test $enable_symvers = darwin)
GLIBCXX_CONDITIONAL(ENABLE_SYMVERS_SUN, test $enable_symvers = sun)
AC_MSG_NOTICE(versioning on shared library symbols is $enable_symvers)

if test $enable_symvers != no ; then
   case ${target_os} in
     # The Solaris 2 runtime linker doesn't support the GNU extension of
     # binding the same symbol to different versions
     solaris2*)
       ;;
     # Other platforms with GNU symbol versioning (GNU/Linux, more?) do.
     *)
       AC_DEFINE(HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT, 1,
	 [Define to 1 if the target runtime linker supports binding the same symbol to different versions.])
       ;;
    esac
fi

# Now, set up compatibility support, if any.
# In addition, need this to deal with std::size_t mangling in
# src/compatibility.cc.  In a perfect world, could use
# typeid(std::size_t).name()[0] to do direct substitution.
AC_MSG_CHECKING([for size_t as unsigned int])
ac_save_CFLAGS="$CFLAGS"
CFLAGS="-Werror"
AC_TRY_COMPILE(, [__SIZE_TYPE__* stp; unsigned int* uip; stp = uip;],
		 [glibcxx_size_t_is_i=yes], [glibcxx_size_t_is_i=no])
CFLAGS=$ac_save_CFLAGS
if test "$glibcxx_size_t_is_i" = yes; then
  AC_DEFINE(_GLIBCXX_SIZE_T_IS_UINT, 1, [Define if size_t is unsigned int.])
fi
AC_MSG_RESULT([$glibcxx_size_t_is_i])

AC_MSG_CHECKING([for ptrdiff_t as int])
ac_save_CFLAGS="$CFLAGS"
CFLAGS="-Werror"
AC_TRY_COMPILE(, [__PTRDIFF_TYPE__* ptp; int* ip; ptp = ip;],
		 [glibcxx_ptrdiff_t_is_i=yes], [glibcxx_ptrdiff_t_is_i=no])
CFLAGS=$ac_save_CFLAGS
if test "$glibcxx_ptrdiff_t_is_i" = yes; then
  AC_DEFINE(_GLIBCXX_PTRDIFF_T_IS_INT, 1, [Define if ptrdiff_t is int.])
fi
AC_MSG_RESULT([$glibcxx_ptrdiff_t_is_i])
])


dnl
dnl Setup to use the gcc gthr.h thread-specific memory and mutex model.
dnl We must stage the required headers so that they will be installed
dnl with the library (unlike libgcc, the STL implementation is provided
dnl solely within headers).  Since we must not inject random user-space
dnl macro names into user-provided C++ code, we first stage into <file>-in
dnl and process to <file> with an output command.  The reason for a two-
dnl stage process here is to correctly handle $srcdir!=$objdir without
dnl having to write complex code (the sed commands to clean the macro
dnl namespace are complex and fragile enough as it is).  We must also
dnl add a relative path so that -I- is supported properly.
dnl
dnl Substs:
dnl  thread_header
dnl
AC_DEFUN([GLIBCXX_ENABLE_THREADS], [
  AC_MSG_CHECKING([for thread model used by GCC])
  target_thread_file=`$CXX -v 2>&1 | sed -n 's/^Thread model: //p'`
  AC_MSG_RESULT([$target_thread_file])
  GCC_AC_THREAD_HEADER([$target_thread_file])
])


dnl
dnl Check if gthread implementation defines the types and functions
dnl required by the c++0x thread library.  Conforming gthread
dnl implementations can define __GTHREADS_CXX0X to enable use with c++0x.
dnl
dnl GLIBCXX_ENABLE_SYMVERS must be done before this.
dnl
AC_DEFUN([GLIBCXX_CHECK_GTHREADS], [
  GLIBCXX_ENABLE(libstdcxx-threads,auto,,[enable C++11 threads support])

  if test x$enable_libstdcxx_threads = xauto ||
     test x$enable_libstdcxx_threads = xyes; then

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS

  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions \
	-I${toplevel_srcdir}/libgcc -I${toplevel_builddir}/libgcc"

  target_thread_file=`$CXX -v 2>&1 | sed -n 's/^Thread model: //p'`
  case $target_thread_file in
    posix)
      CXXFLAGS="$CXXFLAGS -DSUPPORTS_WEAK -DGTHREAD_USE_WEAK -D_PTHREADS"
  esac

  AC_MSG_CHECKING([whether it can be safely assumed that mutex_timedlock is available])

  AC_TRY_COMPILE([#include <unistd.h>],
    [
      // In case of POSIX threads check _POSIX_TIMEOUTS.
      #if (defined(_PTHREADS) \
	  && (!defined(_POSIX_TIMEOUTS) || _POSIX_TIMEOUTS <= 0))
      #error
      #endif
    ], [ac_gthread_use_mutex_timedlock=1], [ac_gthread_use_mutex_timedlock=0])

  AC_DEFINE_UNQUOTED(_GTHREAD_USE_MUTEX_TIMEDLOCK, $ac_gthread_use_mutex_timedlock,
		     [Define to 1 if mutex_timedlock is available.])

  if test $ac_gthread_use_mutex_timedlock = 1 ; then res_mutex_timedlock=yes ;
  else res_mutex_timedlock=no ; fi
  AC_MSG_RESULT([$res_mutex_timedlock])

  AC_MSG_CHECKING([for gthreads library])

  AC_TRY_COMPILE([#include "gthr.h"],
    [
      #ifndef __GTHREADS_CXX0X
      #error
      #endif
    ], [ac_has_gthreads=yes], [ac_has_gthreads=no])
  else
    ac_has_gthreads=no
  fi

  AC_MSG_RESULT([$ac_has_gthreads])

  if test x"$ac_has_gthreads" = x"yes"; then
    AC_DEFINE(_GLIBCXX_HAS_GTHREADS, 1,
	      [Define if gthreads library is available.])

    # Also check for pthread_rwlock_t for std::shared_timed_mutex in C++14
    # but only do so if we're using pthread in the gthread library.
    # On VxWorks for example, pthread_rwlock_t is defined in sys/types.h
    # but the pthread library is not there by default and the gthread library
    # does not use it.
    AC_TRY_COMPILE([#include "gthr.h"],
    [
      #if (!defined(_PTHREADS))
      #error
      #endif
    ], [ac_gthread_use_pthreads=yes], [ac_gthread_use_pthreads=no])
    if test x"$ac_gthread_use_pthreads" = x"yes"; then
      AC_CHECK_TYPE([pthread_rwlock_t],
             [AC_DEFINE([_GLIBCXX_USE_PTHREAD_RWLOCK_T], 1,
             [Define if POSIX read/write locks are available in <gthr.h>.])],
             [],
             [#include "gthr.h"])
    fi
  fi

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])


# Check whether LC_MESSAGES is available in <locale.h>.
# Ulrich Drepper <drepper@cygnus.com>, 1995.
#
# This file file be copied and used freely without restrictions.  It can
# be used in projects which are not available under the GNU Public License
# but which still want to provide support for the GNU gettext functionality.
# Please note that the actual code is *not* freely available.
AC_DEFUN([AC_LC_MESSAGES], [
  AC_CHECK_HEADER(locale.h, [
    AC_CACHE_CHECK([for LC_MESSAGES], ac_cv_val_LC_MESSAGES,
      [AC_TRY_COMPILE([#include <locale.h>], [return LC_MESSAGES],
       ac_cv_val_LC_MESSAGES=yes, ac_cv_val_LC_MESSAGES=no)])
    if test $ac_cv_val_LC_MESSAGES = yes; then
      AC_DEFINE(HAVE_LC_MESSAGES, 1,
		[Define if LC_MESSAGES is available in <locale.h>.])
    fi
  ])
])

dnl
dnl Check whether rdrand is supported in the assembler.
AC_DEFUN([GLIBCXX_CHECK_X86_RDRAND], [
  AC_MSG_CHECKING([for rdrand support in assembler])
  AC_CACHE_VAL(ac_cv_x86_rdrand, [
  ac_cv_x86_rdrand=no
  case "$target" in
    i?86-*-* | \
    x86_64-*-*)
    AC_TRY_COMPILE(, [asm("rdrand %eax");],
		[ac_cv_x86_rdrand=yes], [ac_cv_x86_rdrand=no])
  esac
  ])
  if test $ac_cv_x86_rdrand = yes; then
    AC_DEFINE(_GLIBCXX_X86_RDRAND, 1,
		[ Defined if as can handle rdrand. ])
  fi
  AC_MSG_RESULT($ac_cv_x86_rdrand)
])

dnl
dnl Check whether rdseed is supported in the assembler.
AC_DEFUN([GLIBCXX_CHECK_X86_RDSEED], [
  AC_MSG_CHECKING([for rdseed support in assembler])
  AC_CACHE_VAL(ac_cv_x86_rdseed, [
  ac_cv_x86_rdseed=no
  case "$target" in
    i?86-*-* | \
    x86_64-*-*)
    AC_TRY_COMPILE(, [asm("rdseed %eax");],
		[ac_cv_x86_rdseed=yes], [ac_cv_x86_rdseed=no])
  esac
  ])
  if test $ac_cv_x86_rdseed = yes; then
    AC_DEFINE(_GLIBCXX_X86_RDSEED, 1,
		[ Defined if as can handle rdseed. ])
  fi
  AC_MSG_RESULT($ac_cv_x86_rdseed)
])

dnl
dnl Check whether get_nprocs is available in <sys/sysinfo.h>, and define _GLIBCXX_USE_GET_NPROCS.
dnl
AC_DEFUN([GLIBCXX_CHECK_GET_NPROCS], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  AC_MSG_CHECKING([for get_nprocs])
  AC_CACHE_VAL(glibcxx_cv_GET_NPROCS, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <sys/sysinfo.h>],
      [int n = get_nprocs();],
      [glibcxx_cv_GET_NPROCS=yes],
      [glibcxx_cv_GET_NPROCS=no])
  ])
  if test $glibcxx_cv_GET_NPROCS = yes; then
    AC_DEFINE(_GLIBCXX_USE_GET_NPROCS, 1, [Define if get_nprocs is available in <sys/sysinfo.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_GET_NPROCS)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check whether sysconf(_SC_NPROCESSORS_ONLN) is available in <unistd.h>, and define _GLIBCXX_USE_SC_NPROCESSORS_ONLN.
dnl
AC_DEFUN([GLIBCXX_CHECK_SC_NPROCESSORS_ONLN], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  AC_MSG_CHECKING([for _SC_NPROCESSORS_ONLN])
  AC_CACHE_VAL(glibcxx_cv_SC_NPROCESSORS_ONLN, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <unistd.h>],
      [int n = sysconf(_SC_NPROCESSORS_ONLN);],
      [glibcxx_cv_SC_NPROCESSORS_ONLN=yes],
      [glibcxx_cv_SC_NPROCESSORS_ONLN=no])
  ])
  if test $glibcxx_cv_SC_NPROCESSORS_ONLN = yes; then
    AC_DEFINE(_GLIBCXX_USE_SC_NPROCESSORS_ONLN, 1, [Define if _SC_NPROCESSORS_ONLN  is available in <unistd.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_SC_NPROCESSORS_ONLN)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check whether sysconf(_SC_NPROC_ONLN) is available in <unistd.h>, and define _GLIBCXX_USE_SC_NPROC_ONLN.
dnl
AC_DEFUN([GLIBCXX_CHECK_SC_NPROC_ONLN], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  AC_MSG_CHECKING([for _SC_NPROC_ONLN])
  AC_CACHE_VAL(glibcxx_cv_SC_NPROC_ONLN, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <unistd.h>],
      [int n = sysconf(_SC_NPROC_ONLN);],
      [glibcxx_cv_SC_NPROC_ONLN=yes],
      [glibcxx_cv_SC_NPROC_ONLN=no])
  ])
  if test $glibcxx_cv_SC_NPROC_ONLN = yes; then
    AC_DEFINE(_GLIBCXX_USE_SC_NPROC_ONLN, 1, [Define if _SC_NPROC_ONLN  is available in <unistd.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_SC_NPROC_ONLN)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check whether pthread_num_processors_np is available in <pthread.h>, and define _GLIBCXX_USE_PTHREADS_NUM_PROCESSORS_NP.
dnl
AC_DEFUN([GLIBCXX_CHECK_PTHREADS_NUM_PROCESSORS_NP], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  AC_MSG_CHECKING([for pthreads_num_processors_np])
  AC_CACHE_VAL(glibcxx_cv_PTHREADS_NUM_PROCESSORS_NP, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <pthread.h>],
      [int n = pthread_num_processors_np();],
      [glibcxx_cv_PTHREADS_NUM_PROCESSORS_NP=yes],
      [glibcxx_cv_PTHREADS_NUM_PROCESSORS_NP=no])
  ])
  if test $glibcxx_cv_PTHREADS_NUM_PROCESSORS_NP = yes; then
    AC_DEFINE(_GLIBCXX_USE_PTHREADS_NUM_PROCESSORS_NP, 1, [Define if pthreads_num_processors_np is available in <pthread.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_PTHREADS_NUM_PROCESSORS_NP)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check whether pthread_cond_clockwait is available in <pthread.h> for std::condition_variable to use,
dnl and define _GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT.
dnl
AC_DEFUN([GLIBCXX_CHECK_PTHREAD_COND_CLOCKWAIT], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"
  ac_save_LIBS="$LIBS"
  LIBS="$LIBS -lpthread"

  AC_MSG_CHECKING([for pthread_cond_clockwait])
  AC_CACHE_VAL(glibcxx_cv_PTHREAD_COND_CLOCKWAIT, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <pthread.h>],
      [pthread_mutex_t mutex; pthread_cond_t cond; struct timespec ts; int n = pthread_cond_clockwait(&cond, &mutex, 0, &ts);],
      [glibcxx_cv_PTHREAD_COND_CLOCKWAIT=yes],
      [glibcxx_cv_PTHREAD_COND_CLOCKWAIT=no])
  ])
  if test $glibcxx_cv_PTHREAD_COND_CLOCKWAIT = yes; then
    AC_DEFINE(_GLIBCXX_USE_PTHREAD_COND_CLOCKWAIT, 1, [Define if pthread_cond_clockwait is available in <pthread.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_PTHREAD_COND_CLOCKWAIT)

  CXXFLAGS="$ac_save_CXXFLAGS"
  LIBS="$ac_save_LIBS"
  AC_LANG_RESTORE
])

dnl
dnl Check whether pthread_mutex_clocklock is available in <pthread.h> for std::timed_mutex to use,
dnl and define _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK.
dnl
AC_DEFUN([GLIBCXX_CHECK_PTHREAD_MUTEX_CLOCKLOCK], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"
  ac_save_LIBS="$LIBS"
  LIBS="$LIBS -lpthread"

  AC_MSG_CHECKING([for pthread_mutex_clocklock])
  AC_CACHE_VAL(glibcxx_cv_PTHREAD_MUTEX_CLOCKLOCK, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <pthread.h>],
      [pthread_mutex_t mutex; struct timespec ts; int n = pthread_mutex_clocklock(&mutex, CLOCK_REALTIME, &ts);],
      [glibcxx_cv_PTHREAD_MUTEX_CLOCKLOCK=yes],
      [glibcxx_cv_PTHREAD_MUTEX_CLOCKLOCK=no])
  ])
  if test $glibcxx_cv_PTHREAD_MUTEX_CLOCKLOCK = yes; then
    AC_DEFINE(_GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK, 1, [Define if pthread_mutex_clocklock is available in <pthread.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_PTHREAD_MUTEX_CLOCKLOCK)

  CXXFLAGS="$ac_save_CXXFLAGS"
  LIBS="$ac_save_LIBS"
  AC_LANG_RESTORE
])

dnl
dnl Check whether pthread_mutex_clocklock is available in <pthread.h> for std::timed_mutex to use,
dnl and define _GLIBCXX_USE_PTHREAD_MUTEX_CLOCKLOCK.
dnl
AC_DEFUN([GLIBCXX_CHECK_PTHREAD_RWLOCK_CLOCKLOCK], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"
  ac_save_LIBS="$LIBS"
  LIBS="$LIBS -lpthread"

  AC_MSG_CHECKING([for pthread_rwlock_clockrdlock, pthread_wlock_clockwrlock])
  AC_CACHE_VAL(glibcxx_cv_PTHREAD_RWLOCK_CLOCKLOCK, [
    GCC_TRY_COMPILE_OR_LINK(
      [#include <pthread.h>],
      [pthread_rwlock_t rwl; struct timespec ts;]
      [int n = pthread_rwlock_clockrdlock(&rwl, CLOCK_REALTIME, &ts);]
      [int m = pthread_rwlock_clockwrlock(&rwl, CLOCK_REALTIME, &ts);],
      [glibcxx_cv_PTHREAD_RWLOCK_CLOCKLOCK=yes],
      [glibcxx_cv_PTHREAD_RWLOCK_CLOCKLOCK=no])
  ])
  if test $glibcxx_cv_PTHREAD_RWLOCK_CLOCKLOCK = yes; then
    AC_DEFINE(_GLIBCXX_USE_PTHREAD_RWLOCK_CLOCKLOCK, 1, [Define if pthread_rwlock_clockrdlock and pthread_rwlock_clockwrlock are available in <pthread.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_PTHREAD_RWLOCK_CLOCKLOCK)

  CXXFLAGS="$ac_save_CXXFLAGS"
  LIBS="$ac_save_LIBS"
  AC_LANG_RESTORE
])

dnl
dnl Check whether sysctl is available in <pthread.h>, and define _GLIBCXX_USE_SYSCTL_HW_NCPU.
dnl
AC_DEFUN([GLIBCXX_CHECK_SYSCTL_HW_NCPU], [

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"

  AC_MSG_CHECKING([for hw.ncpu sysctl])
  AC_CACHE_VAL(glibcxx_cv_SYSCTL_HW_NCPU, [
    GCC_TRY_COMPILE_OR_LINK(
      [
       #include <stddef.h>
       #include <sys/sysctl.h>
       ],
      [
       int count;
       size_t size = sizeof(count);
       int mib[] = { CTL_HW, HW_NCPU };
       sysctl(mib, 2, &count, &size, NULL, 0);
      ],
      [glibcxx_cv_SYSCTL_HW_NCPU=yes],
      [glibcxx_cv_SYSCTL_HW_NCPU=no])
  ])
  if test $glibcxx_cv_SYSCTL_HW_NCPU = yes; then
    AC_DEFINE(_GLIBCXX_USE_SYSCTL_HW_NCPU, 1, [Define if sysctl(), CTL_HW and HW_NCPU are available in <sys/sysctl.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_SYSCTL_HW_NCPU)

  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check to see if python pretty printing can be activated.
dnl
dnl --with-python-dir=dir
dnl installs directory into $prefix/dir
AC_DEFUN([GLIBCXX_ENABLE_PYTHON], [

AC_MSG_CHECKING([for custom python install directory])
AC_ARG_WITH([python-dir],
	    AS_HELP_STRING([--with-python-dir],
			   [the location to install Python modules. This path is relative starting from the prefix.]),
	    [with_python_dir=$withval], [with_python_dir="no"])
AC_MSG_RESULT(${with_python_dir})

# Needed for installing Python modules during make install.
python_mod_dir="${with_python_dir}"
AC_SUBST(python_mod_dir)
GLIBCXX_CONDITIONAL(ENABLE_PYTHONDIR, test $python_mod_dir != no)
])

dnl
dnl Check to see if -Werror is disabled.
dnl
dnl --enable-werror/--disable-werror
AC_DEFUN([GLIBCXX_ENABLE_WERROR], [
  AC_MSG_CHECKING([for -Werror])
  GLIBCXX_ENABLE(werror,$1,,[turns on -Werror])
  AC_MSG_RESULT($enable_werror)
  GLIBCXX_CONDITIONAL(ENABLE_WERROR, test $enable_werror = yes)
])

dnl
dnl Check whether obsolescent tmpnam is available in <stdio.h>,
dnl and define _GLIBCXX_USE_TMPNAM.
dnl
AC_DEFUN([GLIBCXX_CHECK_TMPNAM], [dnl
dnl
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"
dnl
  AC_MSG_CHECKING([for tmpnam])
  AC_CACHE_VAL(glibcxx_cv_TMPNAM, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [#include <stdio.h>],
      [char *tmp = tmpnam(NULL);],
      [glibcxx_cv_TMPNAM=yes],
      [glibcxx_cv_TMPNAM=no])
  ])
  if test $glibcxx_cv_TMPNAM = yes; then
    AC_DEFINE(_GLIBCXX_USE_TMPNAM, 1, [Define if obsolescent tmpnam is available in <stdio.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_TMPNAM)
dnl
  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check to see if sys/sdt.h exists and that it is suitable for use.
dnl Some versions of sdt.h were not compatible with C++11.
dnl
AC_DEFUN([GLIBCXX_CHECK_SDT_H], [
  AC_MSG_CHECKING([for suitable sys/sdt.h])
  # Note that this test has to be run with the C language.
  # Otherwise, sdt.h will try to include some headers from
  # libstdc++ itself.
  AC_LANG_SAVE
  AC_LANG_C
  AC_CACHE_VAL(glibcxx_cv_sys_sdt_h, [
    # Because we have to run the test in C, we use grep rather
    # than the compiler to check for the bug.  The bug is that
    # were strings without trailing whitespace, causing g++
    # to look for operator"".  The pattern searches for the fixed
    # output.
    AC_EGREP_CPP([ \",\" ], [
      #include <sys/sdt.h>
      int f() { STAP_PROBE(hi, bob); }
    ], [glibcxx_cv_sys_sdt_h=yes], [glibcxx_cv_sys_sdt_h=no])
  ])
  AC_LANG_RESTORE
  if test $glibcxx_cv_sys_sdt_h = yes; then
    AC_DEFINE(HAVE_SYS_SDT_H, 1,
              [Define to 1 if you have a suitable <sys/sdt.h> header file])
  fi
  AC_MSG_RESULT($glibcxx_cv_sys_sdt_h)
])

dnl
dnl Control whether the library should define symbols for old and new ABIs.
dnl This affects definitions of strings, stringstreams and locale facets.
dnl
dnl --disable-libstdcxx-dual-abi will use old ABI for all types.
dnl
dnl Defines:
dnl  _GLIBCXX_USE_DUAL_ABI (always defined, either to 1 or 0)
dnl
AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_DUAL_ABI], [
  GLIBCXX_ENABLE(libstdcxx-dual-abi,$1,,[support two versions of std::string])
  if test x$enable_symvers = xgnu-versioned-namespace; then
    # gnu-versioned-namespace is incompatible with the dual ABI.
    enable_libstdcxx_dual_abi="no"
  fi
  if test x"$enable_libstdcxx_dual_abi" != xyes; then
    AC_MSG_NOTICE([dual ABI is disabled])
    default_libstdcxx_abi="gcc4-compatible"
  fi
  GLIBCXX_CONDITIONAL(ENABLE_DUAL_ABI, test $enable_libstdcxx_dual_abi = yes)
])

dnl
dnl Check to see which ABI should be enabled by default.
dnl
dnl --with-default-libstdcxx-abi={gcc4-compatible,new}
dnl
dnl Defines:
dnl  _GLIBCXX_USE_CXX11_ABI (always defined, either to 1 or 0)
dnl
AC_DEFUN([GLIBCXX_DEFAULT_ABI], [
  if test x$enable_libstdcxx_dual_abi = xyes; then
  AC_MSG_CHECKING([for default std::string ABI to use])
  AC_ARG_WITH([default-libstdcxx-abi],
    AS_HELP_STRING([--with-default-libstdcxx-abi],
                   [set the std::string ABI to use by default]),
    [case "$withval" in
      gcc4-compatible)  default_libstdcxx_abi="gcc4-compatible" ;;
      new|cxx11)  default_libstdcxx_abi="new" ;;
      c++*|gnu++*) AC_MSG_ERROR([Supported arguments for --with-default-libstdcxx-abi have changed, use "new" or "gcc4-compatible"]) ;;
      *) AC_MSG_ERROR([Invalid argument for --with-default-libstdcxx-abi]) ;;
     esac
     ],
    [default_libstdcxx_abi="new"])
  AC_MSG_RESULT(${default_libstdcxx_abi})
  fi
  if test $default_libstdcxx_abi = "new"; then
    glibcxx_cxx11_abi=1
    glibcxx_cxx98_abi=0
  else
    glibcxx_cxx11_abi=0
    glibcxx_cxx98_abi=1
  fi
  AC_SUBST(glibcxx_cxx98_abi)
  GLIBCXX_CONDITIONAL(ENABLE_CXX11_ABI, test $glibcxx_cxx11_abi = 1)
])

dnl
dnl Check to see whether to build libstdc++fs.a
dnl
dnl --enable-libstdcxx-filesystem-ts
dnl
AC_DEFUN([GLIBCXX_ENABLE_FILESYSTEM_TS], [
  GLIBCXX_ENABLE(libstdcxx-filesystem-ts,auto,,
    [turns on ISO/IEC TS 18822 support],
    [permit yes|no|auto])

  AC_MSG_CHECKING([whether to build Filesystem TS support])
  if test x"$ac_cv_header_dirent_h" != x"yes"; then
    enable_libstdcxx_filesystem_ts=no
  fi
  if test x"$enable_libstdcxx_filesystem_ts" = x"auto"; then
    case "${target_os}" in
      freebsd*|netbsd*|openbsd*|dragonfly*|darwin*)
        enable_libstdcxx_filesystem_ts=yes
        ;;
      gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu | uclinux*)
        enable_libstdcxx_filesystem_ts=yes
        ;;
      rtems*)
        enable_libstdcxx_filesystem_ts=yes
        ;;
      solaris*)
        enable_libstdcxx_filesystem_ts=yes
        ;;
      mingw*)
        enable_libstdcxx_filesystem_ts=yes
        ;;
      *)
        enable_libstdcxx_filesystem_ts=no
        ;;
    esac
  fi
  AC_MSG_RESULT($enable_libstdcxx_filesystem_ts)
  GLIBCXX_CONDITIONAL(ENABLE_FILESYSTEM_TS, test $enable_libstdcxx_filesystem_ts = yes)
])

dnl
dnl Check whether the library calls required by the C++17 Filesystem library
dnl and the Filesystem TS are present.
dnl Defines:
dnl  HAVE_STRUCT_DIRENT_D_TYPE
dnl  _GLIBCXX_USE_REALPATH
dnl  _GLIBCXX_USE_UTIMENSAT
dnl  _GLIBCXX_USE_ST_MTIM
dnl  _GLIBCXX_USE_FCHMOD
dnl  _GLIBCXX_USE_FCHMODAT
dnl  _GLIBCXX_USE_SENDFILE
dnl  HAVE_LINK
dnl  HAVE_READLINK
dnl  HAVE_SYMLINK
dnl
AC_DEFUN([GLIBCXX_CHECK_FILESYSTEM_DEPS], [dnl
dnl
  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS
  ac_save_CXXFLAGS="$CXXFLAGS"
  CXXFLAGS="$CXXFLAGS -fno-exceptions"
dnl
  AC_MSG_CHECKING([for struct dirent.d_type])
  AC_CACHE_VAL(glibcxx_cv_dirent_d_type, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [#include <dirent.h>],
      [
       struct dirent d;
       if (sizeof d.d_type) return 0;
      ],
      [glibcxx_cv_dirent_d_type=yes],
      [glibcxx_cv_dirent_d_type=no])
  ])
  if test $glibcxx_cv_dirent_d_type = yes; then
    AC_DEFINE(HAVE_STRUCT_DIRENT_D_TYPE, 1, [Define to 1 if `d_type' is a member of `struct dirent'.])
  fi
  AC_MSG_RESULT($glibcxx_cv_dirent_d_type)
dnl
  AC_MSG_CHECKING([for realpath])
  AC_CACHE_VAL(glibcxx_cv_realpath, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [
       #include <limits.h>
       #include <stdlib.h>
       #include <unistd.h>
      ],
      [
       #if _XOPEN_VERSION < 500
       #error
       #elif _XOPEN_VERSION >= 700 || defined(PATH_MAX)
       char *tmp = realpath((const char*)NULL, (char*)NULL);
       #else
       #error
       #endif
      ],
      [glibcxx_cv_realpath=yes],
      [glibcxx_cv_realpath=no])
  ])
  if test $glibcxx_cv_realpath = yes; then
    AC_DEFINE(_GLIBCXX_USE_REALPATH, 1, [Define if usable realpath is available in <stdlib.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_realpath)
dnl
  AC_MSG_CHECKING([for utimensat])
  AC_CACHE_VAL(glibcxx_cv_utimensat, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [
	#include <fcntl.h>
	#include <sys/stat.h>
      ],
      [
	struct timespec ts[2] = { { 0, UTIME_OMIT }, { 1, 1 } };
	int i = utimensat(AT_FDCWD, "path", ts, 0);
      ],
      [glibcxx_cv_utimensat=yes],
      [glibcxx_cv_utimensat=no])
  ])
  if test $glibcxx_cv_utimensat = yes; then
    AC_DEFINE(_GLIBCXX_USE_UTIMENSAT, 1, [Define if utimensat and UTIME_OMIT are available in <sys/stat.h> and AT_FDCWD in <fcntl.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_utimensat)
dnl
  AC_MSG_CHECKING([for utime])
  AC_CACHE_VAL(glibcxx_cv_utime, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [
	#include <utime.h>
      ],
      [
	struct utimbuf t = { 1, 1 };
	int i = utime("path", &t);
      ],
      [glibcxx_cv_utime=yes],
      [glibcxx_cv_utime=no])
  ])
  if test $glibcxx_cv_utime = yes; then
    AC_DEFINE(_GLIBCXX_USE_UTIME, 1, [Define if utime is available in <utime.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_utime)
dnl
  AC_MSG_CHECKING([for lstat])
  AC_CACHE_VAL(glibcxx_cv_lstat, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [ #include <sys/stat.h> ],
      [
	struct stat st;
	int i = lstat("path", &st);
      ],
      [glibcxx_cv_lstat=yes],
      [glibcxx_cv_lstat=no])
  ])
  if test $glibcxx_cv_lstat = yes; then
    AC_DEFINE(_GLIBCXX_USE_LSTAT, 1, [Define if lstat is available in <sys/stat.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_lstat)
dnl
  AC_MSG_CHECKING([for struct stat.st_mtim.tv_nsec])
  AC_CACHE_VAL(glibcxx_cv_st_mtim, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [ #include <sys/stat.h> ],
      [
	struct stat st;
	return st.st_mtim.tv_nsec;
      ],
      [glibcxx_cv_st_mtim=yes],
      [glibcxx_cv_st_mtim=no])
  ])
  if test $glibcxx_cv_st_mtim = yes; then
    AC_DEFINE(_GLIBCXX_USE_ST_MTIM, 1, [Define if struct stat has timespec members.])
  fi
  AC_MSG_RESULT($glibcxx_cv_st_mtim)
dnl
  AC_MSG_CHECKING([for fchmod])
  AC_CACHE_VAL(glibcxx_cv_fchmod, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [#include <sys/stat.h>],
      [fchmod(1, S_IWUSR);],
      [glibcxx_cv_fchmod=yes],
      [glibcxx_cv_fchmod=no])
  ])
  if test $glibcxx_cv_fchmod = yes; then
    AC_DEFINE(_GLIBCXX_USE_FCHMOD, 1, [Define if fchmod is available in <sys/stat.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_fchmod)
dnl
  AC_MSG_CHECKING([for fchmodat])
  AC_CACHE_VAL(glibcxx_cv_fchmodat, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [
	#include <fcntl.h>
	#include <sys/stat.h>
      ],
      [fchmodat(AT_FDCWD, "", 0, AT_SYMLINK_NOFOLLOW);],
      [glibcxx_cv_fchmodat=yes],
      [glibcxx_cv_fchmodat=no])
  ])
  if test $glibcxx_cv_fchmodat = yes; then
    AC_DEFINE(_GLIBCXX_USE_FCHMODAT, 1, [Define if fchmodat is available in <sys/stat.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_fchmodat)
dnl
  AC_MSG_CHECKING([for sendfile that can copy files])
  AC_CACHE_VAL(glibcxx_cv_sendfile, [dnl
    case "${target_os}" in
      gnu* | linux* | solaris* | uclinux*)
	GCC_TRY_COMPILE_OR_LINK(
	  [#include <sys/sendfile.h>],
	  [sendfile(1, 2, (off_t*)0, sizeof 1);],
	  [glibcxx_cv_sendfile=yes],
	  [glibcxx_cv_sendfile=no])
	;;
      *)
	glibcxx_cv_sendfile=no
	;;
    esac
  ])
  if test $glibcxx_cv_sendfile = yes; then
    AC_DEFINE(_GLIBCXX_USE_SENDFILE, 1, [Define if sendfile is available in <sys/sendfile.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_sendfile)
dnl
  AC_MSG_CHECKING([for link])
  AC_CACHE_VAL(glibcxx_cv_link, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [#include <unistd.h>],
      [link("", "");],
      [glibcxx_cv_link=yes],
      [glibcxx_cv_link=no])
  ])
  if test $glibcxx_cv_link = yes; then
    AC_DEFINE(HAVE_LINK, 1, [Define if link is available in <unistd.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_link)
dnl
  AC_MSG_CHECKING([for readlink])
  AC_CACHE_VAL(glibcxx_cv_readlink, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [#include <unistd.h>],
      [char buf[32]; readlink("", buf, sizeof(buf));],
      [glibcxx_cv_readlink=yes],
      [glibcxx_cv_readlink=no])
  ])
  if test $glibcxx_cv_readlink = yes; then
    AC_DEFINE(HAVE_READLINK, 1, [Define if readlink is available in <unistd.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_readlink)
dnl
  AC_MSG_CHECKING([for symlink])
  AC_CACHE_VAL(glibcxx_cv_symlink, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [#include <unistd.h>],
      [symlink("", "");],
      [glibcxx_cv_symlink=yes],
      [glibcxx_cv_symlink=no])
  ])
  if test $glibcxx_cv_symlink = yes; then
    AC_DEFINE(HAVE_SYMLINK, 1, [Define if symlink is available in <unistd.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_symlink)
dnl
  AC_MSG_CHECKING([for truncate])
  AC_CACHE_VAL(glibcxx_cv_truncate, [dnl
    GCC_TRY_COMPILE_OR_LINK(
      [#include <unistd.h>],
      [truncate("", 99);],
      [glibcxx_cv_truncate=yes],
      [glibcxx_cv_truncate=no])
  ])
  if test $glibcxx_cv_truncate = yes; then
    AC_DEFINE(HAVE_TRUNCATE, 1, [Define if truncate is available in <unistd.h>.])
  fi
  AC_MSG_RESULT($glibcxx_cv_truncate)
dnl
  CXXFLAGS="$ac_save_CXXFLAGS"
  AC_LANG_RESTORE
])

dnl
dnl Check how size_t is mangled.  Copied from libitm.
dnl
AC_DEFUN([GLIBCXX_CHECK_SIZE_T_MANGLING], [
  AC_CACHE_CHECK([how size_t is mangled],
                 glibcxx_cv_size_t_mangling, [
    AC_TRY_COMPILE([], [extern __SIZE_TYPE__ x; extern unsigned long x;],
                   [glibcxx_cv_size_t_mangling=m], [
      AC_TRY_COMPILE([], [extern __SIZE_TYPE__ x; extern unsigned int x;],
                     [glibcxx_cv_size_t_mangling=j], [
        AC_TRY_COMPILE([],
                       [extern __SIZE_TYPE__ x; extern unsigned long long x;],
                       [glibcxx_cv_size_t_mangling=y], [
          AC_TRY_COMPILE([],
                         [extern __SIZE_TYPE__ x; extern unsigned short x;],
                         [glibcxx_cv_size_t_mangling=t], [
            AC_TRY_COMPILE([],
                           [extern __SIZE_TYPE__ x; extern __int20 unsigned x;],
                           [glibcxx_cv_size_t_mangling=u6uint20],
                           [glibcxx_cv_size_t_mangling=x])
          ])
        ])
      ])
    ])
  ])
  if test $glibcxx_cv_size_t_mangling = x; then
    AC_MSG_ERROR([Unknown underlying type for size_t])
  fi
  AC_DEFINE_UNQUOTED(_GLIBCXX_MANGLE_SIZE_T, [$glibcxx_cv_size_t_mangling],
    [Define to the letter to which size_t is mangled.])
])

dnl
dnl Determine whether std::exception_ptr symbols should be exported with
dnl the symbol versions from GCC 4.6.0 or GCC 7.1.0, depending on which
dnl release first added support for std::exception_ptr. Originally it was
dnl only supported for targets with always-lock-free atomics for int, but
dnl since GCC 7.1 it is supported for all targets.
dnl
AC_DEFUN([GLIBCXX_CHECK_EXCEPTION_PTR_SYMVER], [
  if test $enable_symvers != no; then
    AC_MSG_CHECKING([for first version to support std::exception_ptr])
    case ${target} in
      aarch64-*-* | alpha-*-* | hppa*-*-* | i?86-*-* | x86_64-*-* | \
      m68k-*-* | powerpc*-*-* | s390*-*-* | *-*-solaris* )
        ac_exception_ptr_since_gcc46=yes
        ;;
      *)
        # If the value of this macro changes then we will need to hardcode
        # yes/no here for additional targets based on the original value.
        AC_TRY_COMPILE([], [
          #if __GCC_ATOMIC_INT_LOCK_FREE <= 1
          # error atomic int not always lock free
          #endif
          ],
          [ac_exception_ptr_since_gcc46=yes],
          [ac_exception_ptr_since_gcc46=no])
        ;;
    esac
    if test x"$ac_exception_ptr_since_gcc46" = x"yes" ; then
      AC_DEFINE(HAVE_EXCEPTION_PTR_SINCE_GCC46, 1,
        [Define to 1 if GCC 4.6 supported std::exception_ptr for the target])
      AC_MSG_RESULT([4.6.0])
    else
      AC_MSG_RESULT([7.1.0])
    fi
  fi
])

# Macros from the top-level gcc directory.
m4_include([../config/gc++filt.m4])
m4_include([../config/tls.m4])
m4_include([../config/gthr.m4])
m4_include([../config/cet.m4])