Replace add_newer_entrypoints (src/mesa/main/context.c) with

Replace add_newer_entrypoints (src/mesa/main/context.c) with
device-specific code.  A new Python script
(src/mesa/glapi/extension_helper.py) generates a list of all
entry-points for all known extensions.  Each driver the selects only
the extensions that it needs and enables the via either
driInitExtensions or driInitSingleExtension.

This code has been compile-tested on a drivers, but has only been
run-tested on mga and i915 (on i830 hardware).

These changes were discussed at length on the mesa3d-dev mailing list.

http://marc.theaimsgroup.com/?t=111947074700001&r=1&w=2