output: make wlr_output_set_gamma atomic
wlr_output_set_gamma is now double-buffered and applies the gamma LUT on the next output commit.
Breaking changes:
-
wlr_output_set_gamma
is now double-buffered and applied on the next output commit -
wlr_output_impl.set_gamma
is gone. Backends now need to read the pending output state on commit instead.