anchor.diff:    meta = {
       homepage = http://maude.cs.illinois.edu/;
       description = "High-level specification language";
  -    license = stdenv.lib.licenses.gpl2;
  +    license = stdenv.lib.licenses.gpl2Plus;
   
       longDescription = ''
         Maude is a high-performance reflective language and system
  
positive.code:   postInstall = ''
      for n in "$out/bin/"*; do wrapProgram "$n" --suffix MAUDE_LIB ':' "$out/share/maude"; done
      unzip ${fullMaude}
      install -D -m 444 full-maude.maude $out/share/maude/full-maude.maude
    '';
  
    # bison -dv surface.yy -o surface.c
  
negative.code:   inherit version;
  
    src = fetchurl {
      url = "http://maude.cs.illinois.edu/w/images/9/92/Maude-${version}.tar.gz";
      sha256 = "0vhn3lsck6ji9skrgm67hqrn3k4f6y442q73jbw65qqznm321k5a";
    };
  
    buildInputs = [
      flex bison ncurses buddy tecla gmpxx libsigsegv makeWrapper unzip cln yices
    ];
  
    hardeningDisable = [ "stackprotector" ] ++
  