anchor.diff:  
     postInstall = ''
       for n in "$out/bin/"*; do wrapProgram "$n" --suffix MAUDE_LIB ':' "$out/share/maude"; done
  -    install -D -m 444 ${fullMaude} $out/share/maude/full-maude.maude
  +    unzip ${fullMaude}
  +    install -D -m 444 full-maude.maude $out/share/maude/full-maude.maude
     '';
   
     meta = {
  -    homepage = "http://maude.cs.uiuc.edu/";
  +    homepage = "http://maude.cs.illinois.edu/";
       description = "High-level specification language";
       license = stdenv.lib.licenses.gpl2;
   
  
positive.code: { stdenv, fetchurl, unzip, makeWrapper
  , flex, bison, ncurses, buddy, tecla, libsigsegv, gmpxx,
  }:
  
  let
  
    version = "2.7";
  
    fullMaude = fetchurl {
      url = "https://raw.githubusercontent.com/maude-team/full-maude/master/full-maude27c.maude";
      sha256 = "08bg3gn1vyjy5k69hnynpzc9s1hnrbkyv6z08y1h2j37rlc4c18y";
    };
  
  in
  
negative.code:   name = "maude-${version}";
  
    src = fetchurl {
      url = "http://maude.cs.illinois.edu/w/images/d/d8/Maude-${version}.tar.gz";
      sha256 = "0jskn5dm8vvbd3mlryjxdb6wfpkvyx174wk7ci9a31aylxzpr25i";
    };
  
    buildInputs = [
      flex bison ncurses buddy tecla gmpxx libsigsegv makeWrapper unzip cvc4 cln
    ];
  
    hardeningDisable = [ "stackprotector" ] ++
      stdenv.lib.optionals stdenv.isi686 [ "pic" "fortify" ];
  