pan/lower_blend: bug fixes for gles3.1
Cc @bbrezillon the remaining draw_buffers_indexed fails go away when PAN_MESA_DEBUG=noafbc is passed, so punting the remaining bug to you.
Some of the changes here are just prepping for !10601 (merged)
Cc @bbrezillon the remaining draw_buffers_indexed fails go away when PAN_MESA_DEBUG=noafbc is passed, so punting the remaining bug to you.
Some of the changes here are just prepping for !10601 (merged)