22.1.6

• Updated Mesa3D to 22.1.6.

Build script

• MSYS2: Import credentials from Git for Windows;
• Misc: Avoid Windows where tool internal error messages;
• Misc: Check if Git is available as quickly as possible;
• MSYS2: Always load Git for Windows when available;
• MSYS2: Change currrent directory to Windows current folder;
• MSYS2/Meson: Don't hardcode source code directory;
• MSYS2: Restore option to clear package cache after installing packages;
• OpenCL stack: Make sure we never link against clang-cpp library;
• MSVC: Support using clang build used by clc to build whole Mesa.

Distribution

• MSYS2: Strip lib prefix from Microsoft CLC filename [22.2+].

Build environment updates

• MSYS2 MinGW-w64 GCC
• MSVC