Add support for V3D_DEBUG=clif. Useful to compare clif_dumps from
vulkan small-programs and the equivalent opengl ones.
As we are here we expand clif_dump_packet wrapper to use
v3d42_clif_dump_packet if needed, as the vulkan driver would use that
packet version.
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
Values still doesn't take into account having vertex elements data,
but keeps some of that half-done code in comments. It would be better
to do that when we get an example using it.
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6766>
