[Bug libstdc++/86507] std::filesystem not work on Windows

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86507

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to tower120 from comment #0)
> All 7.x with
> "experimental/filesystem" worked fine.

Are you sure about that? You might be able to include the header, but nothing
else works.

Anyway, this is an exact duplicate of PR 85670, which was already fixed by PR
78870.