anchor.diff:            -initrd ${config.system.build.toplevel}/initrd \
             ${qemuGraphics} \
             $QEMU_OPTS \
  -          -append "$(cat ${config.system.build.toplevel}/kernel-params) init=${config.system.build.bootStage2} systemConfig=${config.system.build.toplevel} ${kernelConsole} $QEMU_KERNEL_PARAMS"
  +          -append "$(cat ${config.system.build.toplevel}/kernel-params) init=${config.system.build.bootStage2} systemConfig=${config.system.build.toplevel} regInfo=${regInfo} ${kernelConsole} $QEMU_KERNEL_PARAMS"
  +    '';
  +
  +    
  +  regInfo = pkgs.runCommand "reginfo"
  +    { exportReferencesGraph =
  +        map (x: [("closure-" + baseNameOf x) x]) config.virtualisation.pathsInNixDB;
  +      buildInputs = [ pkgs.perl ];
  +    }
  +    ''
  +      printRegistration=1 perl ${pkgs.pathsFromGraph} closure-* > $out
       '';
   
   in
  
positive.code:         default = true;
          description =
            ''
              Whether to run qemu with a graphics window, or access
              the guest computer serial port through the host tty.
            '';
        };
  
    };
  
    cfg = config.virtualisation;
  
negative.code:         options = "bind";
          neededForBoot = true;
        }
      ];
  
    # Starting DHCP brings down eth0, which kills the connection to the
  