atkmm 2.51.1 (unstable):

This is the first release of the atkmm-2.26 API/ABI.
It installs in parallel with the atkmm-1.6 API/ABI, of which
the most recent version is atkmm 2.24.2.

* Require C++14.
  (Murray Cumming)
* Use glibmm-2.52 instead of glibmm-2.4.
  (Murray Cumming)
* Fix silent builds.
  (Kjell Ahlstedt) Bug #768797