Package -stable updates

[Steven Shockley]

So, many thanks to everyone who put together the new -stable updates for
packages.  Is there a command I can put in the crontab that will only
output if there are updates?  Similar to what syspatch or openup does.
I tried pkg_add -unx, but that still tells me to delete old files and
prints the quirks line even if there are no updates.