These packages make use of gtk3 useflag which indicates that there are issues of migration to gtk+:3.
Gtk3 and similar useflags should be avoided.
Adding to tracker. Please have a look.
We'll consider simplifying the logic for toolkit selection when Emacs upstream will drop support for GTK+ 2, or when GTK+ upstream will fix bug <http://bugzilla.gnome.org/show_bug.cgi?id=85715> in GTK+ 3. Whatever will occur earlier.