This adds the option to set systemd's default.target in
the System Configuration subheading if systemd is
specified as the init system.
The argument for default.target is specified pre-build
as opposed to overriding the hardcoded "multi-user.target"
symlink with post-build scripts or a rootfs overlay
Signed-off-by: Sen Hastings <sen@phobosdpl.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>