anchor.diff:      sha256 = "1hsxzrjvqa3pd74vmz8agiiwynrzynp1i726h0fzdsakc4adya4l";
     };
   
  -  buildInputs = [ git pythonPackages.python ];
  +  buildInputs = [ git python2Packages.python ];
     nativeBuildInputs = [ pandoc perl makeWrapper ];
   
     postPatch = ''
  
positive.code:     wrapProgram $out/bin/bup \
        --prefix PATH : ${git}/bin \
        --prefix PYTHONPATH : ${concatStringsSep ":" (map (x: "$(toPythonPath ${x})")
          (with pythonPackages;
           [ setuptools tornado ]
           ++ stdenv.lib.optionals (!stdenv.isDarwin) [ pyxattr pylibacl fuse ]))}
    '';
  
negative.code: { stdenv, fetchFromGitHub, fetchurl, makeWrapper
  , perl, pandoc, python2Packages, git
  , par2cmdline ? null, par2Support ? false
  }:
  
  