[libcxx-commits] [libcxx] [RFC][libc++] Use IWYU pragma's. (PR #102191)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne requested changes to this pull request.

My preference would be to instead use 0-1 for `TEST_HAS_XXX` macros, since that also solves the existing problem that our test suite is not safe w.r.t. `-Wundef`. And it would solve the clang-tidy issues since we'd actually use the macro from the header.

https://github.com/llvm/llvm-project/pull/102191