Fixes#45687.
This is really just a band-aid, our current buildsystem doesn't work well for
cross-compilation and needs a thorough refactoring to do so.
Compiling with latest clang on macOS produces this error:
comparison of integers of different signs: 'uint32_t' (aka 'unsigned int') and 'int' [-Werror,-Wsign-compare]
This file is not present in 4.0/master.
- Fix Embree runtime when using MinGW (patch by @RandomShaper).
- Fix baking of lightmaps on GridMaps.
- Fix some GLSL errors.
- Fix overflow in the number of shader variants (GLES2).