anchor.diff:  
   let
   
  -  name = "hylafaxplus-${version}";
  +  pname = "hylafaxplus";
     version = "7.0.3";
     sha256 = "139iwcwrn9i5lragxi33ilzah72w59wg4midfjjgx5cly3ah0iy4";
   
     configSite = substituteAll {
  -    name = "hylafaxplus-config.site";
  +    name = "${pname}-config.site";
       src = ./config.site;
       config_maxgid = lib.optionalString (maxgid!=null) ''CONFIG_MAXGID=${builtins.toString maxgid}'';
       ghostscript_version = ghostscript.version;
  
positive.code: in
  
  stdenv.mkDerivation {
    inherit name version;
    src = fetchurl {
      url = "mirror://sourceforge/hylafax/hylafax-${version}.tar.gz";
      inherit sha256;
  
negative.code:   };
  
    postInstall = substituteAll {
      name = "${pname}-post-install.sh";
      src = ./post-install.sh;
      inherit fakeroot libfaketime;
    };
  