Adding .db support to pkg_tools

[Ollivier Robert]

According to Anders Nore:
> with the base system (/usr/src/include/db.h). BerkeleyDB is not you're 
> typical relational db, and can only save key/value pairs. The way I'm 
> thinking of storing information to the .db is to name the keys as the 
> directory names in /var/db/pkg. And save the +* files in the directories to 
> the value element in the db, separated with a special character or similar.

Please make it compatible with the existing infrastructure in
/var/db/pkg maintained by portinstall/portupgrade.  If it can be improved
as a side-effect, that would be even better.
-- 
Ollivier ROBERT -=- FreeBSD: The Power to Serve! -=- roberto at keltia.freenix.fr
Darwin sidhe.keltia.net Version 9.2.0: Tue Feb  5 16:13:22 PST 2008; i386