glapi: Merge glapioffsets.h into glapidispath.h.

Move defines in glapioffsets.h to glapidispatch.h.  Rename
_gloffset_FIRST_DYNAMIC to _gloffset_COUNT, which is equal to the number
of entries in _glapi_table.

Consistently use SET_by_offset, GET_by_offset, CALL_by_offset, and
_gloffset_* to recursively define all SET/GET/CALL macros.
7 files changed