mesa: Switch to using the Khronos registry for generating enums.

mesa: Switch to using the Khronos registry for generating enums.

I've used a bunch of python code to cut out new enums so that the two
generated files can be diffed.  I'll remove all that hardcoding in the
following commits.  All remaining differences between the generated code:

- GL_TEXTURE_BUFFER_FORMAT didn't appear in GL3 when TBOs got merged to
  core, so it now gets an _ARB suffix instead.

- Blacklisting can't keep EXT_sso's GL_ACTIVE_PROGRAM_EXT from becoming
  GL_ACTIVE_PROGRAM -- in our hash table, GL_ACTIVE_PROGRAM_EXT points at
  the GLES2 enum's value (aka GL_CURRENT_PROGRAM).  By not blacklisting
  the core name, we get both enums translated.

- GL_DRAW_FRAMEBUFFER_BINDING and GL_FRAMEBUFFER_BINDING both appeared in
  GL3 as synonyms, and the new code happens to choose
  GL_FRAMEBUFFER_BINDING instead.

- GL_TEXTURE_COMPONENTS and GL_TEXTURE_INTERNAL_FORMAT both appear in 1.1,
  and the new code chooses GL_TEXTURE_INTERNAL_FORMAT instead (which seems
  better, to me)

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>