Fix crashes when some GLX API entrypoints are called with no current context.

I was hitting this with gliv.

The GLX spec explicitly mentions that glXWaitX, glXWaitGL and glXUseXFont calls
are ignored when there's no current context. Not sure what if anything the
GLX_EXT_texture_from_pixmap spec says about this, but I think ignoring the
calls makes more sense than crashing there as well. :)
1 file changed