On the other hand, if a user installs stuff in /usr/local/ after installing MacPorts it wouldn't help unless selfupdate (and/or port) also checked those paths so maybe it isn't feasible. The Cisco VPN client uses /usr/local, though it causes no problems. Comments?
So the 'problem' is only when the user installs some library in /usr/ local that macports uses and either that install is broken somehow or the user removes it.
It's good to make macports robust against mistakes, but at some point we probably have to realize that end-users are going to be able to configure their systems in ways that are broken, and we may or may not be able to do something about that specific broken-ness.
I agree. Especially since the woes of manually installed OSS is one if the problems MacPorts is trying to overcome. :) Is readline the main offender? I want to document this problem and though I think any non-MP software could potentially be a problem, I might mention the worst offenders as examples. What are others? Mark