while it requires an extra wakeup from vsync thread -> e and this adds
a bit of jitter, it's mroe reliable in the face of "missed a frame"
timings and doesnt degrade as badly.
after i noticed some jitters, it seesms one thread to listen for vsync
events then to wake up the mainloop can suffer from irregular
scheduling jitters. it seems to be highly depenedent on both gpu
driver and cpu but it seemed the vsync thread itself was more reliably
woken than the mainlooop it then signalled, so merging this back is
just batter. it's configurable via an environment variable so we can
try either right now and see, but default is now to be in main loop.
it was a lot of if cases before now it's an array with min version
parameters and globs for matching drivers etc. - much cleaner and
neater to afdd things to the whtielist now.
as per mailing list discussion about dropping xcb support now. it
hasn't been complete for a long time, thus not recommented for being
turned on. as we are moving to a wayland world xcbmakes even less
sense. as agreed, time to clean up a bit and remove a distraction as
well as not well tested code. this also updates po's too.
@feature
Carsten Haitzler
Gustavo Sverzut Barbieri