[PATCH] D54639: [libcxx] Make sure we can build with -fvisibility=hidden on Linux

[Louis Dionne via Phabricator]

ldionne added a comment.

I'm shipping this because I have other changes depending on it and we already reviewed the ABI changes in https://reviews.llvm.org/D53868. Please LMK if you have concerns with this patch and I can revert it or fix them post-commit.


Repository:
  rCXX libc++

https://reviews.llvm.org/D54639