tail, tr: not found when booting

Hi,

I just upgraded my -currnet to today. I noticed that rc complains about
tail and tr not found:

[...]
Trying to mount root from ufs:/dev/ad0s3a
start_init: trying /sbin/init
tail: not found
tr: not found
Loading configuration files.
kernel dumps on /dev/ad0s3b
[...]

The following line in rc.subr looks suspicious

JID=`ps -p $$ -o jid | tail -1 | tr -d ' '`

They should be replaced by absolute name as the rest command in
rc.subr. :-)

Regards,
Rong-En fan