[compiler-rt] [libcxx] [libcxxabi] [libunwind] [libunwind][libcxx][libcxxabi][compiler-rt-builtins] Fix Exception Handling build for wasm (PR #79667)

[Alexander Richardson via cfe-commits]

https://github.com/arichardson commented:

I started reviewing this but all the unrelated formatting changes made this quite difficult. Would appreciate a minimal diff with just the changes that are needed for WASM.

https://github.com/llvm/llvm-project/pull/79667