anchor.diff:      '';
       homepage = http://isabelle.in.tum.de/;
       license = "LGPL";
  +    maintainers = [ stdenv.lib.maintainers.jwiegley ];
     };
   }
  
positive.code: # nettools needed for hostname
  
  let
    dirname = "Isabelle2013";
    theories = ["HOL" "FOL" "ZF"];
  in
  
  stdenv.mkDerivation {
    name = "isabelle-2013";
    inherit dirname theories;
  
    src = fetchurl {
      url = http://isabelle.in.tum.de/dist/Isabelle2013_linux.tar.gz;
      sha256 = "0l17s41hwzma0q2glpxrzic8i6mqd9b7awlpwhz0jkli7fj6ny7b";
    };
  
    buildInputs = [ perl polyml nettools ];
  
    sourceRoot = dirname;
  
    patches = [ ./settings.patch ];
  
    postPatch = ''
      ENV=$(type -p env)
  
negative.code:       --replace /usr/bin/env $ENV
      substituteInPlace lib/Tools/install \
        --replace /usr/bin/env $ENV
      substituteInPlace etc/settings \
        --subst-var-by ML_HOME "${polyml}/bin" \
        --subst-var-by PROOFGENERAL_HOME "${proofgeneral}/share/emacs/site-lisp/ProofGeneral"
    '';
  
    buildPhase = ''
      ./bin/isabelle build -s $theories
    '';
  
    installPhase = ''
      mkdir -p $out/bin
      mv $TMP/$dirname $out
      cd $out/$dirname
      bin/isabelle install $out/bin
    '';
  
    meta = {
  