anchor.diff:    makeFlags =
       [ "ECHO_E_BIN_ECHO=echo" "ECHO_E_BIN_ECHO_E=echo" # No /bin/echo here.
         "ISOLINUX_BIN_LIST=${syslinux}/share/syslinux/isolinux.bin"
  -    ];
  +    ] ++ lib.optional (embedScript != null) "EMBED=${embedScript}";
   
   
     enabledOptions = [ "DOWNLOAD_PROTO_HTTPS" ];
  
positive.code:     ln -s undionly.kpxe $out/undionly.kpxe.0
    '';
  
    meta = with stdenv.lib;
      { description = "Network boot firmware";
        homepage = http://ipxe.org/;
  
negative.code: { stdenv, lib, fetchgit, perl, cdrkit, syslinux, xz, openssl
  , embedScript ? null
  }:
  
  let
    date = "20170922";
  