Update guide to tell user where to get "original" Portfile for patching

[jfcaron3]

If you read: ​https://guide.macports.org/#development.patches.portfile

It tells you how to make a copy and generate patch for a Portfile, but it does not tell you where to find the original Portfile. Looking on my system with find /opt/local grep|portname|grep Portfile, I find two candidates, one somewhere in /opt/local/var/macports/sources/rsync.macports.org/release/tarballs/ports and another somewhere in /opt/local/var/macports/registry/portfiles/ and they appear slightly different.

Even if this is an idiosyncrasy in my system, the guide section should include the default location of the Portfile to be used to generate patches.

[kencu (Ken)]

I find your best bet is to sudo copy the original Portfile in it's original location to Portfile.orig, make your edits to Portfile, and then diff them with diff -u Portfile.orig Portfile > ~/Desktop/somename.diff

Or go the github way instead, if you're going to do this at all frequently.

[ryandesign (Ryan Carsten Schmidt)]

The command port file foo will tell you where the Portfile for port foo is located.

The registry contains a copy of the Portfile as it appeared when you installed the port. This may not be the current version of the Portfile, and if you're going to submit a patch, it should be based on the current version, which is in the sources directory, or, as Ken said, in our GitHub repository.

[jfcaron3]

Those are both good suggestions. One or both methods should be mentioned in the Portfile patches section of the Guide.