mpi found where the r300 driver would not load on macppc due to an
undefined drisw_create_screen symbol.
The code related to that symbol was removed sometime after Mesa 11.0
branched.
Initial diff from and ok mpi@
operations and older CPUs lack the needed instructions. The hardware
supported by that driver will never be used together those older CPUs.
This might mean that even the software rasterizer doesn't work anymore on
those. But they're so slow that you probably wouldn't want to anyway.
ok jsg@
