initial import of mesa 21.3.7

main changes since 19.1.7 include:
- more support for Vulkan functions
- better supported for newer radeonsi (both amdgpu and radeon backends)
- various bug fixes in many drivers
- many fixes and enhancements for intel drivers
- some fixes for nvidia
- OpenGL 4.6 for some drivers (intel, radeonsi)
- intel Tigerlake and Rocketlake support
- Vulkan 1.2 for some drivers
- OpenGL 4.5, GLES 3.2, and more on llvmpipe
- working Panfrost and Midgard drivers
- fix warnings in radeonsi vs newer llvm