Native bindings to the GLX_EXT_visual_rating extension.

This extension allows servers to identify a particular GLX visual as undesirable. A new visual attribute is introduced, providing a way for servers to specify caveats (e.g., slow) for a visual. The attribute may be queried using GetConfig, and can therefore be used by application-specific visual selection routines. The new attribute is also used by ChooseVisual to discriminate against visuals with caveats.

This extension allows servers to export visuals with improved features or image quality, but lower performance or greater system burden, without having to have these visuals selected preferentially. It is intended to insure that most applications get the "right" visual, not that all applications do.