Related to https://projects.blender.org/blender/blender/pulls/147994 in which clang-cl builds failed passing the Windows SDK libraries paths to the compiler. The previous CMake implementation tried to reverse engineer these paths at CMake configuration time but failed with `clang-cl`. The environment variables set by vcvars that could have been useful aren't always available when cmake is called, so now we keep the `LIB` environment variable intact at compile time and pass the other additional compiler libraries paths - that are better defined at CMake configuration time - separately through `-L` compiler arguments. Pull Request: https://projects.blender.org/blender/blender/pulls/148035