Mesa 22.0 Zink Lands macOS Build Fix For OpenGL On Vulkan Via MoltenVK On Metal

Last year there was some work for getting Gallium3D Zink working on macOS for this OpenGL-on-Vulkan implementation to in turn run it atop the MoltenVK library for translating the Vulkan calls to Apple's Metal graphics/compute API. That work fell into disrepair but now the fixed up code for allowing Zink to build on Apple's operating system has been merged into Mesa 22.0...