porting this stuff back.
* Test /etc/motd for writability before trying to update it. This is
especially useful when /etc/ is mounted ro, like on a diskless boot.
(Thanks to phk for the idea on this one.)
* Make the "updating" message reflect what actually happens.
while. This is only the script pieces, the glue for the build comes next.
Submitted by: Mike Makonnen <makonnen@pacbell.net>
Reviewed by: silence on -current and -hackers
Prodded by: rwatson
