spice-vdagentd.socket listens OK but when the session agent starts the daemon falls over with: spice-vdagentd: bind /var/run/spice-vdagentd/spice-vdagent-sock: Address already in use spice-vdagentd: Fatal the server socket /var/run/spice-vdagentd/spice-vdagent-sock exists already. Delete it? systemd: Failed to start Agent daemon for Spice guests. Fixed by adding eautoreconf to the ebuild. Maybe also fixes bug 651102. It will then automagically use GTK+, fixed by adding --with-gtk=yes/no to econf. I've built with both and both seem to work (limited testing).
*** This bug has been marked as a duplicate of bug 651102 ***