[clang] Clang tooling generated visibility macros for Clang (PR #109702)

[Saleem Abdulrasool via cfe-commits]

compnerd wrote:

> But this before we do that, we need to have some kind of mechanism in place so we can actually enumerate the AP However, we already expose everything in the API, and just adding the annotations doesn't change that (although I think it may slightly reduce the number of symbols we export

I think that this is quite accurate. The overall exported symbol count should be reduced with the desired changes as we would default to hidden visibility and then restore the symbols that are needed.

https://github.com/llvm/llvm-project/pull/109702