On Debian sysinit is not a single script but a separate runlevel.
Split of fsck.target into separate unit file as otherwise we get an
unbreakable cycle on shutdown/reboot.
Some unit shall never be start on user request (e.g. shutdown.target)
others never be stopped on user request (e.g. auditd.servce), hence
offer options for both.
This patch gives minimal Arch support (enough to boot).
We still need to parse the services to start from /etc/rc.conf before systemd can be a drop-in replacement on Arch.
