* Passes through PAM (pam_systemd module) via login(1). This sets up
systemd --user instance, which will create and listen on dbus session socket.
* login(1) is called (via agetty(8)) with -p option, keeping the environment
pam_systemd configured for the user, most importantly
DBUS_SESSION_BUS_ADDRESS.
* Thus dbus-launch call in /etc/X11/xinit/xinitrc is unnecessary.
* autologin.conf drop-in configured in the template unit (getty@.service)
to make autologin work on all virtual consoles.
