I wonder if the following workaround may be accepted.

Have a shell script, /bin/prt-get (programs from /bin take precedence over those from /usr/bin with the default settings), use the real prt-get for all cases except when only the sysup argument is used, when it will 'depinst' the new deps before doing the 'sysup'.

This way we can handle the cases when ports are combined too  (when we get file override errors and some has to be removed first).