[all-commits] [llvm/llvm-project] 1ad7de: Headers: exclude `#include_next <stdatomic.h>` on ...

[Saleem Abdulrasool via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1ad7de9e92bc2977698e5f6d6493202b50c912d5
      https://github.com/llvm/llvm-project/commit/1ad7de9e92bc2977698e5f6d6493202b50c912d5
  Author: Saleem Abdulrasool <compnerd at compnerd.org>
  Date:   2021-11-24 (Wed, 24 Nov 2021)

  Changed paths:
    M clang/lib/Headers/stdatomic.h

  Log Message:
  -----------
  Headers: exclude `#include_next <stdatomic.h>` on MSVC

The 14.31.30818 toolset has the following in the `stdatomic.h`:
~~~
 #ifndef __cplusplus
 #error <stdatomic.h> is not yet supported when compiling as C, but this is planned for a future release.
 #endif
~~~

This results in clang failing to build existing code which relied on
`stdatomic.h` in C mode on Windows.  Simply fallback to the clang header
until that header is available as a complete implementation.