Adding a local directory for distfile fetching

[Jeremy Lavergne]

> Thanks for your answer. Would a simple ftp server suffice?

Yes. You can see some of the variables used here:
http://trac.macports.org/browser/trunk/base/src/package1.0/portarchivefetch.tcl#L53

> Besides, how to deal with the fact that source tarballs are not directly stored in the distfiles directory, but rather in a sub-directory whose name corresponds to that of the port?

As far as distfiles (the "distfiles" directory) go, you can mount over the entire directory: those are only needed to perform a source build. After the fact, they can be deleted or unmounted.

The binary archives (the "software" directory) must remain present on the system so it would be best to have these files transferred (ftp/http/scp/rsync).