Is pkgtools/mksandbox supposed to be cross platform?

[Lloyd Parkes <lloyd%must-have-coffee.gen.nz@localhost>]

I see that the Makefile says not for Darwin so that makes it sound like 
other non-NetBSD platforms are allowed.

On the other hand it uses null mounts which I'm not sure is a Linux 
thing. (I don't have a Linux system within arm's reach right now).

Ngā mihi,
Lloyd