[clang] [clang][win] Fix __global_delete wrappers for Arm64EC and cross-TU ::delete (PR #209585)

[Daniel Paoliello via cfe-commits]

dpaoliello wrote:

> I assume you chose to use /alternatename originally because that's what MSVC uses? Is there any issue with mixing /alternatename with weak aliases?

The original implementation tried to (incorrectly) use weak symbols. I'm not sure why I didn't try weak aliases, but in the confusion of that initial PR `/alternatename` seemed to be working, but break down for Arm64EC since the backend has no visibility into them and so does generate any of the thunk support or do any of the symbol mangling that may be required.

Weak aliases is what the latest version of MSVC is using, do we are aligning to that behavior.

https://github.com/llvm/llvm-project/pull/209585