[libclc] [llvm] [libclc][CMake] Use llvm-ar/llvm-ranlib on Windows, Fix flag prefix for clang-cl (PR #186726)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 commented:

This seems strange, though admittedly I know little to nothing about MSVC. I thought the idea was that we only supported a runtimes build going through a just-built clang? Why do we expect MSVC to be used. I haven't seen any other projects require these flag prefixes so I'm skeptical.

https://github.com/llvm/llvm-project/pull/186726