makepkg: remove GITFLAGS support
Supporting git source fragments (branch, commit, tag) is difficult in conjunction with GITFLAGS usage - particularly with the most common use cases that reduce the amount of data cloned from the upstream repo.
Leaving GITFLAGS in place an documenting that various git source features are not supported when GITFLAGS are in used is not an ideal 'solution'. Instead, remove GITFLAGS support.
Signed-off-by: Allan McRae allan@archlinux.org