[libcxx-commits] [libcxx] [libc++] Add missing conditionals for feature-test macros (PR #80168)

[Mark de Wever via libcxx-commits]

https://github.com/mordante approved this pull request.

>From a manual review this LGTM. I wonder whether we can test this better in the CI.

https://github.com/llvm/llvm-project/pull/80168