sources should be stored. E.g. "nixos-checkout /home/eelco/srcs"
will check out to /home/eelco/srcs/{nixos,nixpkgs}. Probably the
/etc/nixos default should be removed eventually because /etc is a
pretty weird place to keep large source trees.
svn path=/nixos/trunk/; revision=34086
was never intended as a generic "check out anything" script; it's
just a convenience script to obtain the NixOS trunk after
installation. So that's what it should do.
svn path=/nixos/trunk/; revision=27005