autogen.sh: Implement GNOME Build API
autogen.sh: Implement GNOME Build API

http://people.gnome.org/~walters/docs/build-api.txt

Signed-off-by: Adam Jackson <4482611cc290c2ce1399431891dcb9221c95f994@redhat.com>

wzyy2/xf86-video-modesetting,wzyy2/xf86-video-modesetting,patjak/xf86-video-gma500,patjak/xf86-video-gma500