I'm trying to build mail/cucipop.  It tells me:

  The supported build options for this package are:

        db inet6

  The currently selected options are:

        inet6

I want to use the 'db' options, since makevpopdb doesn't work without 
it.  (Yes, I'll file a PR on that.)  Just how to do that is unclear.

I have set

	PKG_OPTIONS.cucipop+=db

in mk.conf.  It complains, though, that "db4 is not an acceptable Berkeley DB"
when I do the build.  I worked around that by saying

	_BDB_TYPE=db2 make

but that's ugly.  What's the right thing to put into mk.conf for this?  
RingTFM has not enlightened me.

		--Steven M. Bellovin, http://www.cs.columbia.edu/~smb