[libcxx-commits] [libcxx] [libc++][modules] Add a header to forward-declare std::get (PR #108285)

[Nikolas Klauser via libcxx-commits]

philnik777 wrote:

> > If this solves a non modules-specifc issue I'd expect a test.
> 
> This is already caught by our existing tests. If you remove `__fwd/complex.h`, some modules tests should fail. And when you do the top-level modularization like I did in my other patch, you definitely run into this issue (that's how I found out about this problem).

This also adds forward declarations for `variant` though, which didn't exist before AFAICT.

https://github.com/llvm/llvm-project/pull/108285