Log Message:
atkmm: updated to 2.24.3

atkmm 2.24.3 (stable):
* Fix silent builds.
* 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.
* Replace the Visual Studio project files with MSVC NMake project files