merge mesa 21.3.7.

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

Import mesa 19.1.7

New features in mesa 19.1.0:

GL_ARB_parallel_shader_compile on all drivers.
GL_EXT_gpu_shader4 on all GL 3.1 drivers.
GL_EXT_shader_image_load_formatted on radeonsi.
GL_EXT_texture_buffer_object on all GL 3.1 drivers.
GL_EXT_texture_compression_s3tc_srgb on Gallium drivers and i965 (ES extension).
GL_NV_compute_shader_derivatives on iris and i965.
GL_KHR_parallel_shader_compile on all drivers.
VK_EXT_buffer_device_address on Intel and RADV.
VK_EXT_depth_clip_enable on Intel and RADV.
VK_KHR_ycbcr_image_arrays on Intel.
VK_EXT_inline_uniform_block on Intel and RADV.
VK_EXT_external_memory_host on Intel.
VK_EXT_host_query_reset on Intel and RADV.
VK_KHR_surface_protected_capabilities on Intel and RADV.
VK_EXT_pipeline_creation_feedback on Intel and RADV.
VK_KHR_8bit_storage on RADV.
VK_AMD_gpu_shader_int16 on RADV.
VK_AMD_gpu_shader_half_float on RADV.
VK_NV_compute_shader_derivatives on Intel.
VK_KHR_shader_float16_int8 on Intel and RADV (RADV only supports int8).
VK_KHR_shader_atomic_int64 on Intel.
VK_EXT_descriptor_indexing on Intel.
VK_KHR_shader_float16_int8 on Intel and RADV.
GL_INTEL_conservative_rasterization on iris.
VK_EXT_memory_budget on Intel.

New features in mesa 19.0.0:

GL_AMD_texture_texture4 on all GL 4.0 drivers.
GL_EXT_shader_implicit_conversions on all drivers (ES extension).
GL_EXT_texture_compression_bptc on all GL 4.0 drivers (ES extension).
GL_EXT_texture_compression_rgtc on all GL 3.0 drivers (ES extension).
GL_EXT_render_snorm on gallium drivers (ES extension).
GL_EXT_texture_view on drivers supporting texture views (ES extension).
GL_OES_texture_view on drivers supporting texture views (ES extension).
GL_NV_shader_atomic_float on nvc0 (Fermi/Kepler only).
Shader-based software implementations of GL_ARB_gpu_shader_fp64, GL_ARB_gpu_shader_int64, GL_ARB_vertex_attrib_64bit, and GL_ARB_shader_ballot on i965.
VK_ANDROID_external_memory_android_hardware_buffer on Intel
Fixed and re-exposed VK_EXT_pci_bus_info on Intel and RADV
VK_EXT_scalar_block_layout on Intel and RADV
VK_KHR_depth_stencil_resolve on Intel
VK_KHR_draw_indirect_count on Intel
VK_EXT_conditional_rendering on Intel
VK_EXT_memory_budget on RADV

Also, bug fixes.

initial import of mesa-18.3.6

from maya:

Import mesa 18.3.4.

Mesa 18.3.4 implements the OpenGL 4.5 API.
Some drivers don't support all the features required in OpenGL 4.5.

initial import of MesaLib-10.3.5