This directory contains the build system. In consists mainly of makefile
templates for different directory roles.

:'global.mk': This file contains global variables, for example the
  definitions of the tools to use.

:'generic.mk': Generic rules for creating file types from others.

:'prg.mk': This file represents the target binary role of a directory.
  It must be included by all makefiles that build programs.

:'lib.mk': This file represents a library role. It is never used from
  within the 'src/' directory but only from the <libname>.mk files
  in 'lib/mk/'.
