anchor.diff:                           "${config.networking.hostName}\n"));
                     
                     virtualisation.qemu.options =
  -                    lib.flip lib.concatMapStrings interfacesNumbered ({ first, second }:
  -                      "-net nic,vlan=${toString second},model=virtio " +
  -                      # Use 232.0.1.<vlan> as the multicast address to
  -                      # connect VMs on the same vlan, but allow it to
  -                      # be overriden using the $QEMU_MCAST_ADDR_<vlan>
  -                      # environment variable.  The test driver sets
  -                      # this variable to prevent collisions between
  -                      # parallel builds.
  -                      "-net socket,vlan=${toString second},mcast=" +
  -                      "\${QEMU_MCAST_ADDR_${toString first}:-232.0.1.${toString first}:1234} "
  -                    );
  -
  +                    lib.flip lib.concatMapStrings interfacesNumbered
  +                      ({ first, second }: qemuNICFlags second first );
                   };
               }
             )
  
positive.code: 
      in lib.listToAttrs nodes_;
  
      
    # Zip two lists together.  Should be moved to pkgs.lib.
    zip = xs: ys:
      if xs != [] && ys != [] then
  
negative.code: let pkgs = import nixpkgs { config = {}; inherit system; }; in
  
  with pkgs;
  with import ../lib/qemu-flags.nix;
  
  rec {
  
  