plugins?
      ( dev-libs/gobject-introspection >=dev-libs/libpeas-1.0.0 ||
            ( dev-libs/gmime:3.0[vala] dev-libs/gmime:2.6[vala] )
       )

terminal?
      ( x11-libs/vte:2.91 )

||
      ( >=dev-libs/gmime-3.0.3:3.0 >=dev-libs/gmime-2.6.21:2.6 )

dev-cpp/glibmm:2
>=dev-cpp/gtkmm-3.10:3.0
dev-libs/boost[nls]
dev-libs/libsass
>=dev-libs/protobuf-3.6.0:=[protobuf]
||
      ( >=net-libs/webkit-gtk-2.22.0:4.1= >=net-libs/webkit-gtk-2.22.0:4= )

net-mail/notmuch