Previously, a specific file or directory could be compiled with custom
CFLAGS by adding a Makefile variable such as:
CFLAGS_dlmalloc.o = <custom flags for common/dlmalloc.c>
or
CFLAGS_lib = <custom flags for lib directory>
This method breaks down once multiple files or directories share the
same path. Eg FLAGS_fileA = <custom flags> would incorrectly result in
both dir1/fileA.c and dir2/fileA.c being compiled with <custom flags>.
This change allows finer grained control which we need once we move
lib_$ARCH to arch/$ARCH/lib/ and lib_generic/ to lib/. Without this
change all lib/ directories would share the same custom CFLAGS.
Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
