[libcxx-commits] [libcxx] [libcxx] Use generic builtins for popcount, clz and ctz (PR #86563)

[Mark de Wever via libcxx-commits]

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

I've updated the CI and it now runs `Ubuntu clang version 19.0.0 (++20240409031520+c8917048e3aa-1~exp1~20240409151624.1609)`. Can you rebase the patch to trigger the CI?

LGTM when the CI passes.

https://github.com/llvm/llvm-project/pull/86563