atkmm 2.25.4 (unstable):
Distro packagers should probably not package this yet.

* Build: Use glibmm-2.56 instead of glibmm-2.54.
  We have changed the ABI name in glibmm.
  (Murray Cumming)
* Text: Plug memory leaks in get_text_vfunc() and get_selection_vfunc().
  These vfuncs shall delete the returned character array after it has been
  copied to a Glib::ustring.
  (Kjell Ahlstedt) Bug #783360