configure.ac: Require the latest glibmm.
configure.ac: Require the latest glibmm.

To use the latest gmmproc, which generates more move operations,
and to have the latest Glib::Object/ObjectBase/Interface which have
move operations that those generated move operations call.

GNOME/atkmm,GNOME/atkmm,GNOME/atkmm,GNOME/atkmm