[libcxx-commits] [libcxx] [libc++] fixing missing forward declarations of uses_allocator_construction_args (PR #67044)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne requested changes to this pull request.

I think this looks pretty good to me, but I am struggling to figure whether there's other similar cases that would be problematic and for which we should add test coverage.

@philnik777 can you take a look since you wrote this in the first place?

https://github.com/llvm/llvm-project/pull/67044