Plugin_VideoOGL: X11: Add another display connection to keep the two threads from
eating each others events.
Manifests itself in GPU thread waiting forever for a reply in GL library code(and thus
a frozen emulation). Most of the time, this can be resolved by creating more events
(clicking, changing focus), but sometimes it stays stuck.
Make shader for copying from depth buffer to texture more resilent against precision loss.
The theoretical result is slightly different to the original shader because the
final adjustment is to the range [0/255..255/255] instead of
The real result is vastly different on some gpus that were giving incorrect results
of bits 23..16 (y-component) wrapping around while bits 31..24 (z-component)
stayed the same, and bits 31..24 changing while in the middle of the value range
for bits 23..16 for large depth values.
This should fix issue #3123.