[clang] Fix math-errno issue (PR #66381)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

The logic makes sense to me, but it would be nice if we had a second set of eyes on this given how dense the code is. @jcranmer-intel how does this seem to you?

https://github.com/llvm/llvm-project/pull/66381