[Mesa-dev] softpipe/draw: add support for vertex streams

[Dave Airlie]

This adds support for an ARB_gpu_shader5 feature, multiple
vertex streams, I initially wrote this a few years ago, and
decided to revisit it since virglrenderer is using softpipe
in it's CI and it might be nice to get closer to GLES3.1

This doesn't give use ARB_gpu_shader5 yet, but I think
it might be worth enabling it, as nearly everything that is
left is multi-sampling related, and we don't support that properly
anyways.

Dave.