MSVC: Move dirent implementation to glib/dirent/
It is used only by libglib when built with MSVC, it's not worth a generic build/
top directory, especially since it's common with meson to use build/
as build directory.
It is used only by libglib when built with MSVC, it's not worth a generic build/
top directory, especially since it's common with meson to use build/
as build directory.