[libcxx-commits] [libcxxabi] [libc++abi] Revert gating of `__cxa_thread_atexit` on Linux||Fuchsia (PR #186054)

[Andrew Kaster via libcxx-commits]

ADKaster wrote:

FWIW fixing this issue 'properly' as suggested by @outtersg would also remove a need for a patch on SerenityOS that looks remarkably similar to the current state of this PR:
https://github.com/SerenityOS/serenity/blob/5f2bd52d8dfa16d79e1b1cc66d01523e1447a690/Toolchain/Patches/llvm/0007-libcxxabi-Define-__cxa_thread_atexit-on-serenity.patch

https://github.com/llvm/llvm-project/pull/186054