[PATCH] D45470: Emit an error when mixing <stdatomic.h> and <atomic>

[Volodymyr Sapsai via Phabricator via cfe-commits]

vsapsai added a comment.

Thanks for the review, Marshall.

In the end I removed `XFAIL: with_system_cxx_lib` from libc++ test as the change is header-only at compile time. Library behaviour at runtime shouldn't be affected.


Repository:
  rC Clang

https://reviews.llvm.org/D45470