- Only update when pixmap content actually change;
- Only update the regions that acutally changed.
This is a worthwhile optimization, but it doesn't completely remove
the bottleneck, as mesa still uploads then entire texture whenever
it changes.
Add GL_ARB_texture_non_power_of_two, GL_EXT_framebuffer_object and
GL_NV_texture_env_combine4 extensions.
Add __GLXcontext destructor and flush context cache there and on
loseCurrent.
Chain back to new __GLXcontext destructor. (__glXMesaContextForceCurrent):
Set render table on forceCurrent. (init_screen_visuals): Index pVis
array correctly. (GlxGetMesaProvider): Add this.
Hook up FBO marshalling.
