[PATCH] D34918: [libc++] Avoid atomic built-ins for NO_THREADS build

[Eric Fiselier via Phabricator via llvm-commits]

EricWF added a comment.

Why don't you start by adding `__libcpp_sync_foo` functions that we can use, then we can decide on what macros to use to guard their definition.

I'm not exactly sure where the `__libcpp_sync_foo` functions should live since they have to be used in `__refstring`, but I would just put wherever works at first.


Repository:
  rL LLVM

https://reviews.llvm.org/D34918