1) perf build
=============
The perf build process consists of several separated building blocks,
which are linked together to form the perf binary:
  - libperf library (static)
  - perf builtin commands
  - traceevent library (static)
  - GTK ui library

Several makefiles govern the perf build:

  - Makefile
    top level Makefile working as a wrapper that calls the main
    Makefile.perf with a -j option to do parallel builds.

  - Makefile.perf
    main makefile that triggers build of all perf objects including
    installation and documentation processing.

  - tools/build/Makefile.build
    main makefile of the build framework

  - tools/build/Build.include
    build framework generic definitions

  - Build makefiles
    makefiles that defines build objects

Please refer to tools/build/Documentation/Build.txt for more
information about build framework.


2) perf build
=============
The Makefile.perf triggers the build framework for build objects:
   perf, libperf, gtk

resulting in following objects:
  $ ls  *-in.o
  gtk-in.o  libperf-in.o  perf-in.o

Those objects are then used in final linking:
  libperf-gtk.so <- gtk-in.o  libperf-in.o
  perf           <- perf-in.o libperf-in.o


NOTE this description is omitting other libraries involved, only
     focusing on build framework outcomes