ignore "portfile changed" ?

[Ken Cunningham]

when working on the destrooting of complex ports it is tedious to have the ports rebuild with each portfile edit, esp the big ports that need the complex destrooting....

It must be possible to override this -- I feel I'm missing something simple somewhere. I hope this detail is not just buried in the guide somewhere that I missed.

Sometimes I copy the build dir into /tmp and then back again, but this doesn't always work.