The reason for having the standard provides at all, or the reason
they
are in mingw-filesystem? The reason for having them at all is just
for uniformity. You can "BuildRequires: mingw(wsock32.dll)" and not
care whether that comes from Windows/Wine or from Fedora.
The reason they are in mingw-filesystem and not in mingw-crt is likely
just because we put them there without thinking about it too much.
(Or "filesystem" is the system environment).
Anyway moving them seem sensible, I have no objections.
Done, I've also added a README to mingw-filesystem documenting the steps
to build the environment [1].
Sandro
[1]
https://src.fedoraproject.org/rpms/mingw-filesystem/blob/rawhide/f/README.md