Going from 8.0-CURRENT to RELENG_7

This is basically a warning and an advise -- as usual -- YMMV.

I have missed HEADS-UP that RELENG_7 has been branched and found myself
running 8.0 after cvsup/buildworld/installworld cycle. Since I wanted to
stick to RELENG_7 and since branching occured 2 days ago, I've figured I
should be able to change tag in SUPFILE cvsup and rebuild.

Hence the warning: *don't do that* -- buildworld failed midway with 

/libexec/ld-elf.so.1: Undefined symbol "__mb_sb_limit" referenced from
COPY relocation in sh.

and you are left with non-working system.

Now the advice part: *do not despair* -- you can boot into single user
mode, use /rescue/sh, manually copy

/bin/sh
/usr/bin/make
/usr/bin/awk
/usr/sbin/mtree
/usr/sbin/zic
/lib/libedit.so.6
/lib/libncurses.so.7

from your OBJ directory, then do 'make installworld' twice (something
non-important failed in the first pass) and you should be back in
business.

Hopefully, everyone on the list reads it diligently and does not need
such advice, but if you shot yourself in the foot, here is the chance to
avoid reinstalling the system from scratch.

-- 
Alexandre "Sunny" Kovalenko.