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

[Nikita Popov via llvm-commits]

nikic wrote:

> Should we consider enabling -Wmissing-prototypes so this doesn't regress in the future?

Assuming you mean -Wmissing-declarations, that does sound like a good idea to me... Would also catch missing `static` modifiers on functions.

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