anchor.diff:  # Run time
   , ncurses, readline, gmp, mpfr, expat, zlib, dejagnu
   
  -, pythonSupport ? stdenv.hostPlatform == stdenv.buildPlatform && !stdenv.hostPlatform.isCygwin, python ? null
  +, pythonSupport ? stdenv.hostPlatform == stdenv.buildPlatform && !stdenv.hostPlatform.isCygwin, python3 ? null
   , guile ? null
   
   }:
  
positive.code:   nativeBuildInputs = [ pkgconfig texinfo perl setupDebugInfoDirs ];
  
    buildInputs = [ ncurses readline gmp mpfr expat zlib guile ]
      ++ stdenv.lib.optional pythonSupport python
      ++ stdenv.lib.optional doCheck dejagnu;
  
    propagatedNativeBuildInputs = [ setupDebugInfoDirs ];
  
negative.code:   version = "8.2";
  in
  
  assert pythonSupport -> python3 != null;
  
  stdenv.mkDerivation rec {
    name =
  