The Vulkan driver wants to be able to delete fragment outputs that are beyond key.nr_color_regions; this is a lot easier if we lower outputs at specialization time rather than link time. (Rationale added to commit message by Ken) Signed-off-by: Jason Ekstrand <jason.ekstrand@intel.com> Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>