> I would say that :
> * NetBSD's ``build'' target performs mostly the same as FreeBSD's
>  ``buildworld'';
> * NetBSD's ``buildworld'' performs the same as FreeBSD's
>   ``installworld'' with DESTDIR=/some/path;
> * NetBSD's ``installworld'' is used to install the fresh system
>   standing in /some/path into /;
> * Finally, using NetBSD's ``distribution'' with an empty DESTDIR
>   makes ``installworld'' useless.

building distribution should populate DESTDIR and create base.tgz, etc.
However, using build.sh is much nicer than directly messing with Makefile;
invoke it without args to see the possible targets.