From the Changelog of bpython-0.14 (see URL): The GTK+ frontend has been removed. Hence it is not necessary to still have a 'gtk' useflag together with the accompanying dependencies on pygtk and pygobject.
Thanks 19 Feb 2015; Andrey Grozin <grozin@gentoo.org> bpython-0.14.ebuild: Cleanup, closing #540574