[clang] [clang-tools-extra] [llvm] [clang] Introduce diagnostics suppression mappings (PR #112517)

[Nikita Popov via cfe-commits]

nikic wrote:

It looks like this increases time to build clang by 0.5% (see affected files here: https://llvm-compile-time-tracker.com/compare_clang.php?from=e385e0d3e71e17da0b2023f480259c95923707bd&to=41e3919ded78d8870f7c95e9181c7f7e29aa3cc4&stat=instructions%3Au&sortBy=interestingness)

This usually indicates that you are including something expensive in a core header -- it would be good to check whether it can be avoided.

https://github.com/llvm/llvm-project/pull/112517