[llvm] [LLVM] Silence compiler-rt warning in runtimes build (PR #99525)

[Saleem Abdulrasool via llvm-commits]

https://github.com/compnerd approved this pull request.

How do `LLVM_CONFIG_PATH` and `LLVM_CMAKE_PATH` interact? If they don't then, we should be good.

https://github.com/llvm/llvm-project/pull/99525