pkgsrc doesn't know how to create users and groups on Darwin/Mac OS X.
There's no useradd(8) available, nor any easy equivalent, but I've
determined the magic sequence of commands (about a dozen) that does it.
groupadd(8), too.

I'm going to have me a little fun and turn this information into
shell-script clones of user(8) and group(8) for Darwin. Once that's
done, where should they go? Does it makes sense to have sysutils/user do
one thing for NetBSD and another for Darwin, since the resulting
installed software would perform the same function and (at least mostly)
work the same way?

- Amitai