2.5 and cxx_stdlib

[Vincent Habchi]

> Just a reminder that MacPorts 2.5 will check whether ports are built
> against the right C++ standard library as part of rev-upgrade. The

Also, as part of this new check, a column is added to the registry, so please be sure to run a first ‘port outdated’ or whatever using sudo, otherwise you get an error message telling you the registry is read only and cannot be altered.

Vincent