[libcxx-commits] [libcxx] [libc++][test] Use `TEST_MEOW_DIAGNOSTIC_IGNORED` instead of `ADDITIONAL_COMPILE_FLAGS` (PR #75133)

[Stephan T. Lavavej via libcxx-commits]

StephanTLavavej wrote:

I'll prepare another PR to go back to the original approach, keeping the uncontroversial improvements of this approach.

https://github.com/llvm/llvm-project/pull/75133