Comment # 8 on bug 1205109 from Dr. Werner Fink

Btw:

I see for

  sudo emacs-gtk
  XDG_RUNTIME_DIR (/run/user/223) is not owned by us (uid 0), but by uid 223!
(This could e.g. happen if you try to connect to a non-root PulseAudio as a
root user, over the native protocol. Don't do that.)

this is an error I guess