hook so we can upload a subset of a pixmap, and convert the current
drivers to respect that. Use this support to directly UploadToScreen in
exaGlyphs, providing a 47.4% +/-2.4% decrease in wall time for ls -lR
programs/Xserver in an antialiased gnome-terminal on an M6 (n=3, caches
hot). I would have bumped major version, only I can't tell what the
EXA_VERSION_* is supposed to be doing as opposed to the module version.