[libcxx-commits] [libcxx] [libc++][format] Disables the FTM on older MacOS versions. (PR #126547)

[Louis Dionne via libcxx-commits]

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

LGTM. I was able to reproduce the issue locally by using an older deployment target. Also, we were already using `// XFAIL: availability-fp_to_chars-missing` on the format tests due to this issue.

https://github.com/llvm/llvm-project/pull/126547