[libcxx-commits] [libcxx] Revert "[libc++] Remove workaround which allows setting _LIBCPP_OVERRIDABLE_FUNC_VIS externally (#113139)" (PR #117779)

[Louis Dionne via libcxx-commits]

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

LGTM but I'd like @philnik777 to stamp this as well.

https://github.com/llvm/llvm-project/pull/117779