This information can be read by the "runlevel" command as well as "halt"
and "reboot". Having the information logged in /var/run/runlevel as
well as the utmp file means systems without utmp (like those running
the musl C library) can still check the current runlevel. This is
useful when running halt/reboot as these programs want to check the
runlevel.
Updated the changelog, and manual pages for halt and runlevel.
from /var/run/runlevel. Added test code to runlevel.c to confirm it works.
Will use this to save/restore runlevel on systems where utmp is not
available.
