2.90.3.1 (unstable):

Build:
* Split atkmm of into a separate tarball, like pangomm.
  This allows gtkmm-2.4 and gtkmm-3.0 to use the same atkmm ABI.
  (Daniel Elstner)
* Build against gtk+ from git master too.
  (Chris Kühl)

Gtk:
* StatusBar: Added remove_all()
* TextView: Added get_hadjustment(), get_vadjustment(),
  im_context_filter_keypress(), and reset_im_context().
  (Murray Cumming)