[llvm] Fix warnings while building llvm against emscripten for web assembly (PR #118262)

[Sam Clegg via llvm-commits]

sbc100 wrote:

I know there are other folks who are focused on building llvm for Wasm.  I wonder why they haven't found a need to do this?  Can you not perhaps globally configure llvm for static linking perhaps?

https://github.com/llvm/llvm-project/pull/118262