glib/glibmm/meson.build: Use glibmm-int rule for all builds
glib/glibmm/meson.build: Use glibmm-int rule for all builds

Let builds from release tarballs and GIT checkouts build the glibmm-int
static library, and link the final .so/.dll from the objects that form
glibmm-int static .lib.  By doing so we can build glibmm with the import
libraries for Visual Studio builds with gendef, as well as linking in
the version resource for all Windows builds.

GNOME/glibmm,GNOME/glibmm,GNOME/glibmm,GNOME/glibmm,GNOME/glibmm