install fails because / is not writeable

[Björn König]

> Once in a while a port fails to upgrade, because it wants to write
> something in /etc. E.g. perl into /etc/make.conf or other ports into
> /etc/group.
>
> On my systems / is normally a read only mount. These ports build fine
> during a portupgrade and fail during install, leaving most of the port
> installed, but unregistered (i.e. the package database is broken).
>
> [...]

Mount / writable before upgrading or installing software.

Regards
Björn