[libcxx-commits] [libcxx] [libc++] Make std::unique_lock available with _LIBCPP_HAS_NO_THREADS (PR #99562)

[Paul Kirth via libcxx-commits]

ilovepi wrote:

The bots seem to be running into an error w/ missing definitions for error codes.  From what I can tell, `no-threads` shouldn't affect the availability of error codes.

In my local build I can reproduce the same error when compiling the test w/ `-D_LIBCPP_NO_THREADS=1`. I checked the preprocessed output, and noticed it referenced a module. Removing module related flags `-fmodules -fcxx-modules -fmodule-cache-path=...` stops the error from occurring. I'm unclear on why that would happen though. 

@ldionne have you encountered this type of issue before? Is there a way to avoid this behavior?

https://github.com/llvm/llvm-project/pull/99562