[llvm] [LLVM] Fix missing includes for function declarations that will be needed for explicit symbol visibility (PR #103900)

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

LGTM

(Can also solve most of these by removing no longer needed LegacyPM passes, but it's fine to land this in the meantime.)

https://github.com/llvm/llvm-project/pull/103900