If "-O2 -pipe -march=prescott" should not be used, then I suppose gnustep-gui
should use
libpng-config --I_opts
instead of
libpng-config --cflags
when deciding what compiler flags to use.
gnustep-make does not filter compiler flags that you explicitly specify in the
GNUmakefile;
they are used as they are. That's by design; it would be frustrating to have
gnustep-make
interfere with them. So, if you add -O2 -march=prescott to
ADDITIONAL_INCLUDE_DIRS
you are basically forcing these flags to always be used. If you don't want
that to happen,
well, don't add them there! ;-)