1. New variable DEPENDS lets you list packages that this depends on,
relative to the top (lang/tcl, x11/tk, etc). These packages will
always get made first.
2. Don't configure again if you've already done so successfully.
3. Add pre-configure and post-configure hooks. You can now do a pre-configure,
a local configure, a port-provided configure and finally a post-configure
if you really really want to. I can't imagine anything this will leave us
not being able to do! :) [ Yes, I have actually found a use for at least
two of these in one port - see x11/tk!].
Submitted by: jkh
