port xyz: the grey screen with all the checkboxes is wrong and won't come back

[Steve Franks]

Obviously, 'make clean' doesn't reset the configure screen.  Don't know why.

I recall there was a faster way to fix this than 'portsnap extract'
but I'll be damned if I can remember, and the ports section of the
handbook doesn't even mention configure dialogs...

I'd love to add a snippet to the handbook to cover this, but the last
time I made an offer like that on doc at freebsd, it appears to have gone
into dev/null...

Steve