[clang] [Sema] Don't drop weak_import from a declaration that follows a declaration directly contained in a linkage-specification (PR #85886)

[John McCall via cfe-commits]

https://github.com/rjmccall commented:

I think you're right about the intended logic being to check for a definition, especially given the wording of the warning.  IIRC, we didn't have some of these high-level checks at the time.

With that said, I think you need to check if a definition exists at all and not just whether the last declaration is that definition.

https://github.com/llvm/llvm-project/pull/85886