[BUG] Does not build with clang-cl

[R-Goc]

Describe the bug
Due to adding the /MP option to MSVC like compilers, benchmark doesn't build on clang-cl or icx-cl as they don't handle it in any way, and will throw an unused command line option warning. Due to -Werror this will cause the compilation to fail.

System
Which OS, compiler, and compiler version are you using:

• OS: Windows 11
• Compiler and version: Clang-cl 19

To reproduce
Steps to reproduce the behavior:

1. sync to commit ... master
2. cmake -Bbuild -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_LINKER=lld-link -DCMAKE_C_COMPILER=clang-cl -DCMAKE_CXX_COMPILER=clang-cl
3. cmake --build build
4. See error

Expected behavior
Builds with no modification to cmakelists (removing MP solves it).
The solution would be checking if it is clang, and if so omitting /MP. Not sure how to check for icx.

Screenshots

Additional context
Also should affect icx-cl, as it is based on clang.