[compiler-rt] [dfsan] Support glibc 2.38 __isoc23_* functions (PR #79958)

[Michał Górny via llvm-commits]

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

Thanks a lot! I can confirm that all tests pass with this patch, for me. I also love the simplification!

https://github.com/llvm/llvm-project/pull/79958