update from 6 to 7 - needs libtool rebuild

[Lowell Gilbert]

John Hein <jhein at timing.com> writes:

> So my question is: is this documented and/or widely known?  A full
> portupgrade wouldn't help if you were up to date on libtool in 6.x
> before updating (unless portupgrade -f is used).

But you've *always* needed to rebuild *all* your ports when system
libraries got a version bump.  Symbol versioning may make this less of
an issue in the future, but even then I'll be expecting to do it when I
make major version jumps.

> Would it be worth documenting this in UPDATING (if I haven't
> missed it somewhere)?

It's in the release notes for every (I think) release.  Other places
might make sense also, I guess...