This is the first cut of my switch-over to separate destroot and install
targets. Check out the jkh-destrootification branch if you'd like to (please)
help me test this before it gets merged to TOT at some point. Many, many
ports were changed as a result of this switch-over, so if you see your
port in this commit you might also give it a quick once-over to see if
everything looks (and builds/installs) correct. Thanks!
