Proprosed break in libGL / DRI driver ABI

[Ian Romanick]

Adam Jackson wrote:

> I have another one:  Hide all the functions that start with XF86DRI*, and 
> expose them to the driver through a function table or glXGetProcAddress 
> rather than by allowing the driver to call them directly.  This will simplify 
> the case where the X server is itself linked against libGL.
> 
> Kevin tells me these functions were never intended to be public API anyway.

The only functions that are still used by DRI_NEW_INTERFACE_ONLY drivers 
are XF86DRICreateDrawable, XF86DRIDestroyDrawable, and 
XF86DRIDestroyContext.  It should be easy enough to eliminate those, but 
something other than gLXGetProcAddress might be preferable.