anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "haproxy";
  -  version = "2.5.3";
  +  version = "2.5.4";
   
     src = fetchurl {
       url = "https://www.haproxy.org/download/${lib.versions.majorMinor version}/src/${pname}-${version}.tar.gz";
  -    sha256 = "sha256-1vo8ZvcH/5O1vSfOaecKiWTXtweFSLUYaNR9ffOUP+Q=";
  +    sha256 = "sha256-3EAV2Fx/74EbRZgDt2MAHYCbB6klHcGGT+25oHtErvs=";
     };
   
     buildInputs = [ openssl zlib ]
  
positive.code:       hardware.
      '';
      homepage = "https://haproxy.org";
      license = licenses.gpl2;
      maintainers = with maintainers; [ fuzzy-id ];
      platforms = with platforms; linux ++ darwin;
    };
  
negative.code: 
    # TODO: make it work on bsd as well
    makeFlags = [
      "PREFIX=${placeholder "out"}"
      ("TARGET=" + (if stdenv.isSunOS  then "solaris"
               else if stdenv.isLinux  then "linux-glibc"
               else if stdenv.isDarwin then "osx"
  