[clang] [llvm] [openmp] [openmp][WebAssembly] add support for wasm64 (PR #181669)

[Sam Clegg via llvm-commits]

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@@ -155,7 +155,7 @@ endif()
 # with either the Emscripten or wasi-threads flavor ends up using the pthreads
 # interface in a WebAssembly-compiled libc; CMake does not yet know how to
 # detect this.
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sbc100 wrote:

Hmm, we should probably fix this.

Actually I think this is maybe just not true.  We have test for this in Emscripten: https://github.com/emscripten-core/emscripten/blob/2073d7dd3176253344561b2bef84073baa568298/test/cmake/threads/CMakeLists.txt#L5-L9.

Perhaps we can clean this up separately, no need to make it part of this PR

https://github.com/llvm/llvm-project/pull/181669