Rebuild after Xcode update?

[skip at pobox.com]

I'm currently using Xcode 2.2.1 and am having trouble building the Python
2.5 port.  A little searching suggested I should update my Xcode, so I'm
downloading the Xcode 2.5 image as I write this.

Once I've updated my Xcode installation, what should I do on the MacPorts
side of things?  Is there some way to say "rebuild all" or do I just plow
ahead with the Python 2.5 install and ignore the fact that everything else
was built up to that point with Xcode 2.2.1?

Thanks,

Skip Montanaro