anchor.diff:  stdenv.mkDerivation rec {
     pname = "libxslt";
     version = "1.1.34";
  +
  +  outputs = [ "bin" "dev" "out" "man" "doc" ] ++ lib.optional pythonSupport "py";
   
     src = fetchurl {
       url = "http://xmlsoft.org/sources/${pname}-${version}.tar.gz";
  
positive.code:     description = "A C library and tools to do XSL transformations";
      license = licenses.mit;
      platforms = platforms.all;
      maintainers = [ maintainers.eelco ];
      broken = !(pythonSupport -> libxml2.pythonSupport); # see #73102 for why this is not an assert
    };
  }
  
negative.code:     })
    ];
  
    nativeBuildInputs = [
      pkg-config
    ];
  
    buildInputs = [
      libxml2.dev
    ] ++ lib.optional stdenv.isDarwin [
      gettext
    ] ++ lib.optionals pythonSupport [
      libxml2.py
      python
    ] ++ lib.optionals cryptoSupport [
      libgcrypt
    ];
  
    propagatedBuildInputs = [
      findXMLCatalogs
    ];
  
    configureFlags = [
      "--without-debug"
      "--without-mem-debug"
      "--without-debugger"
    ] ++ lib.optionals pythonSupport [
      "--with-python=${python}"
    ] ++ lib.optionals (!cryptoSupport) [
      "--without-crypto"
    ];
  
    postFixup = ''
      moveToOutput bin/xslt-config "$dev"
  