anchor.diff:      "--without-debug"
       "--without-mem-debug"
       "--without-debugger"
  -  ] ++ optional pythonSupport "--with-python=${python}"
  -    ++ optional (!cryptoSupport) "--without-crypto";
  +  ] ++ stdenv.lib.optional pythonSupport "--with-python=${python}"
  +    ++ stdenv.lib.optional (!cryptoSupport) "--without-crypto";
   
     postFixup = ''
       moveToOutput bin/xslt-config "$dev"
       moveToOutput lib/xsltConf.sh "$dev"
       moveToOutput share/man/man1 "$bin"
  -  '' + optionalString pythonSupport ''
  +  '' + stdenv.lib.optionalString pythonSupport ''
       mkdir -p $py/nix-support
       echo ${libxml2.py} >> $py/nix-support/propagated-build-inputs
       moveToOutput ${python.libPrefix} "$py"
  
positive.code:   outputs = [ "bin" "dev" "out" "man" "doc" ] ++ stdenv.lib.optional pythonSupport "py";
  
    buildInputs = [ libxml2.dev ]
      ++ stdenv.lib.optionals pythonSupport [ libxml2.py python ]
      ++ stdenv.lib.optionals cryptoSupport [ libgcrypt ];
  
  
negative.code: { stdenv, fetchurl, fetchpatch, libxml2, findXMLCatalogs, gettext, python, libgcrypt
  , cryptoSupport ? false
  , pythonSupport ? stdenv.buildPlatform == stdenv.hostPlatform
  }:
  
  stdenv.mkDerivation rec {
    pname = "libxslt";
  