anchor.diff:  }:
   
   let
  -  version = "1.6.34";
  +  version = "1.6.35";
   in
   stdenv.mkDerivation rec {
     name = "libpng-${version}";
  
positive.code:   src = fetchurl {
      url = "mirror://sourceforge/libpng/libpng16/${version}/${name}.tar.xz";
      hashOutput = false;
      sha256 = "2f1e960d92ce3b3abd03d06dfec9637dfbd22febf107a536b44f7a47c60659f6";
    };
  
    buildInputs = [
  
negative.code:   patches = [
      (fetchurl {
        url = "mirror://sourceforge/libpng-apng/libpng16/${version}/${name}-apng.patch.gz";
        sha256 = "18ceb239857bbd32ca706cdad29f1a5dcfb87a5c54258db3bb077cff78c12e04";
      })
    ];
  
  