anchor.diff:  { stdenv, fetchurl, zlib ? null, zlibSupport ? true, bzip2, pkgconfig, libffi
  -, sqlite, openssl, ncurses, pythonFull }:
  +, sqlite, openssl, ncurses, pythonFull, expat }:
   
   assert zlibSupport -> zlib != null;
   
  
positive.code:       #  --replace "return library_dirs" "return tuple(\"{expat}\", *library_dirs)"
      '';
  
      passthru = {
        inherit zlibSupport;
        libPrefix = "pypy${majorVersion}";
  
negative.code:   majorVersion = "2.0";
    version = "${majorVersion}.2";
  
    pypy = stdenv.mkDerivation rec {
      name = "pypy-${version}";
  
      inherit majorVersion version;
  
      src = fetchurl {
        url = "https://bitbucket.org/pypy/pypy/downloads/pypy-${version}-src.tar.bz2";
        sha256 = "0g2cajs6m3yf0lak5f18ccs6j77cf5xvbm4h6y5l1qlqdc6wk48r";
      };
  
      buildInputs = [ bzip2 openssl pkgconfig pythonFull libffi ncurses sqlite ]
        ++ stdenv.lib.optional (stdenv ? gcc && stdenv.gcc.libc != null) stdenv.gcc.libc
        ++ stdenv.lib.optional zlibSupport zlib;
  
      preConfigure = ''
        substituteInPlace Makefile \
          --replace "-Ojit" "-Ojit --batch" \
          --replace "pypy/goal/targetpypystandalone.py" "pypy/goal/targetpypystandalone.py --withmod-_minimal_curses --withmod-unicodedata --withmod-thread --withmod-bz2"
  
        # we are using cpython and not pypy to do translation
        substituteInPlace rpython/bin/rpython \
  