import/switch of:
init, getty, reboot, halt, shutdown, wall, write
changes:
. change reboot() call to netbsd prototype and args
. allows pristine <utmp.h>
. use clean <sys/reboot.h> instead of <minix/reboot.h>
. implement TIOCSCTTY for use by getty so getty can get
controlling terminal from init's child(ren)
Change-Id: I97e137c7fb106ca478d9e1bdc360e77f6b96a376
