This is needed by glamor egl in the xserver which is in turn needed
to get acceleration with some hardware on xf86-video-ati.
Worked on during s2k15. Glamor is not yet enabled in the xserver,
but adding this now as libepoxy recently showed up in ports.
The libepoxy port will be removed and ports will transition to
this version. The xenocara version will be enabled when we're
ready to transition.
