[libcxx-commits] [libcxx] [libc++][NFC] Refactor _LIBCPP_AVAILABILITY_HAS_* macros to always be defined (PR #71002)

[Louis Dionne via libcxx-commits]

ldionne wrote:

It happens here: https://github.com/llvm/llvm-project/blob/main/libcxx/vendor/llvm/default_assertion_handler.in#L20

https://github.com/llvm/llvm-project/pull/71002