In a mess with libc++ libstdc++ and OSX 10.7.5 Lion

[db]

On 14 Sep 2017, at 13:25, Ian Wadham <iandw.au at gmail.com> wrote:
> On 14/09/2017, at 7:57 PM, db wrote:
>> In case you have Time Machine or a clone, just restore /opt/local/ and /Applications/MacPorts/.
> Heh, heh!  Someone else suggested that and it was also one of the first things I
> thought of.  But guess what.  I have TimeMachine, but my settings exclude
> backing up /opt/local and several other build/object-code areas, on the basis that
> they are large and the wherewithal to re-create them is easily available elsewhere.
> in source-code directories, MacPorts servers, etc.

I didn't intend to re-post a suggestion, but that one missed the second path (see man porthier).

I also had my prefix excluded from Time Machine until I encountered some bug in vim that went for weeks unresolved. Not worth the time and you can always delete older backups to make room in your disk. From then on I try to port upgrade right after a TM backup. This is just pragmatic. You could use git branch as others proposed, but I presume you'll end up with a full set of older dependencies for some ports.

You might want to try your most used tools first in a VM with 10.12 or 10.13. Also, in addition to the migration page, check https://trac.macports.org/wiki/SierraProblems.