Comment # 10 on bug 908167 from Jiri Slaby

(In reply to Takashi Iwai from comment #9)
> Usually gnomesu is used for XFCE.
> 
> And, indeed, if you run "su -c env | grep XDG_RUNTIME_DIR", it shows
> "/run/user/0".  Interestingly, it's set so no matter whether the directory
> actually is present or not.

Ok, I see. It looks weird to set the path to an non-existant dir, but at least
it does not corrupt the user's directory. Leaving to apply the patch.