Renamed struct gl_context to struct __GLcontextRec.
Include glcore.h, setup GL imports/exports.
Replaced gl_ prefix with _mesa_ prefix in context.[ch] functions.
GLcontext's Visual field is no longer a pointer.
- FX bug fixes.
- Polygon mode and edgeflag work properly.
- Clipping works with edgeflag.
- Driver.ReducedPrimitiveChange() callback so drivers
that implement lines & points as triangles can turn culling off
before rendering groups of these primitives.
- Cleaned up feedback & select primitives.