anchor.diff:        property shared by most LZ compression algorithms, such as zlib.
       '';
       homepage = "https://facebook.github.io/zstd/";
  +    changelog = "https://github.com/facebook/zstd/blob/v${version}/CHANGELOG";
       license = with licenses; [ bsd3 ]; # Or, at your opinion, GPL-2.0-only.
   
       platforms = platforms.all;
  
positive.code: 
  stdenv.mkDerivation rec {
    pname = "zstd";
    version = "1.4.5";
  
    src = fetchFromGitHub {
      owner = "facebook";
      repo = "zstd";
      rev = "v${version}";
      sha256 = "0ay3qlk4sffnmcl3b34q4zd7mkcmjds023icmib1mdli97qcp38l";
    };
  
    nativeBuildInputs = [ cmake ]
  
negative.code: { stdenv, fetchFromGitHub, cmake, bash, gnugrep
  , fixDarwinDylibNames
  , file
  , legacySupport ? false
  