Upgrading Jails

[David Allen]

I have a test system where I've accumulated a large number of jails.  To
update them (I'm not using the method outlined in the Handbook), I'd like
to avoid mounting /usr/src and /usr/obj within each and then jexec-ing a
shell but instead, perform everything on the host system directly.  Would
the following be appropriate?

 /etc/rc.d/jail stop
 cd /usr/src
 myjail=/home/jails/myjail
 mergemaster -p -t $myjail/var/tmp/temproot -D $myjail
 make installworld DESTDIR=$myjail
 mergemaster -t $myjail/var/tmp/temproot -D $myjail
 ...
 /etc/rc.d/jail start

The second question relates to applying patches.  One of the latest
security advisories, for example, provides these instructions:

 cd /usr/src
 patch < /path/to/patch
 cd /usr/src/lib/bind
 make obj && make depend && make && make install
 cd /usr/src/usr.sbin/named
 make obj && make depend && make && make install
 /etc/rc.d/named restart

Can the "make install" part be modified to include DESTDIR?

Thanks.