port example that extracts pkg

[Ken Cunningham]

there are actually not too many examples in the ports tree of this:

fuse/osxfuse/Portfile
security/1password-cli/Portfile

and perhaps
science/SDRplay/Portfile
science/SDRplay3/Portfile


osxfuse seems to be doing it well, and I'll use that one for an example, for any others that come along with this question.

I think that should let me make progress.

Ken