glx: Support direct rendering pbuffers

We've supported indirect rendering pbuffers for a while, but not direct
rendering pbuffers.  The way we do this is by creating a hidden pixmap
and wrap that in a GLX pbuffer.  This only works when we have DRI2 on
the server, but if the server doesn't have DRI2, it won't expose configs
with pbuffer bits enabled.
1 file changed