anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "exiv2";
  -  version = "0.27.3";
  +  version = "0.27.4";
   
     outputs = [ "out" "dev" "doc" "man" ];
   
  
positive.code: { lib, stdenv
  , fetchFromGitHub
  , fetchpatch
  , zlib
  , expat
  , cmake
  
negative.code:     owner = "exiv2";
      repo  = "exiv2";
      rev = "v${version}";
      sha256 = "0m1x79q6i5fw3gr9k0dw0bbl7ym27g9vbmxiamks6yw028xqwc5a";
    };
  
    nativeBuildInputs = [
      cmake
  