[Mesa-dev] Thread queue for shader cache compression/writes V2

[Timothy Arceri]

This series was created to attempt to address regressions in compile times
cause by the shader cache when the cache is cold. However my testing has
shown no noticable change either way in start-up times of Deus Ex on my
Intel i5-6400 CPU.

The reports were for slow compression times on an older AMD cpu so maybe
it will help more there.

It's also possible this will help in-game but I have no stats for that
currently.

V2: hide thread queue from caller