`clang-cl -help` shows that `-x` is supported directly. It was added by #68921 to support CUDA/HIP. But `clang-cl -x c++-module` report an error ``` unsupported option '-x c++-module'; did you mean '/TC' or '/TP'? ``` Support `-x` for clang-cl, so that we can use `/clang:` to compile C++20 modules (#64118).
