anchor.diff:        rev = "v${version}";
         owner = "coreos";
         repo = "rkt";
  -      sha256 = "094pqxcn91g1s3f0ly3z2lb11s4q3dn99h8cr7lqalkd0gj9l4xg";
  +      sha256 = "0hy6b0lyjsh0m1ca7hga31nybrbi9wpf8c59wbzvm1wlnqzsjkqi";
     };
   
     stage1BaseImage = fetchurl {
  
positive.code:   stage1Flavours = [ "coreos" "fly" ];
  
  in stdenv.mkDerivation rec {
    version = "1.9.1";
    name = "rkt-${version}";
    BUILDDIR="build-${name}";
  
  
negative.code: 
    installPhase = ''
      mkdir -p $out/bin
      cp -Rv $BUILDDIR/target/bin/* $out/bin
      wrapProgram $out/bin/rkt \
        --prefix LD_LIBRARY_PATH : ${systemd}/lib \
        --prefix PATH : ${iptables}/bin
  