anchor.diff: -{ lib, stdenv, fetchurl, coreutils, nettools, java, polyml, z3, veriT, vampire, eprover-ho, rlwrap, makeDesktopItem }:
  +{ lib, stdenv, fetchurl, coreutils, nettools, java, scala, polyml, z3, veriT, vampire, eprover-ho, rlwrap, perl, makeDesktopItem }:
   # nettools needed for hostname
   
   stdenv.mkDerivation rec {
  
positive.code: 
    buildPhase = ''
      export HOME=$TMP # The build fails if home is not set
      bin/isabelle build -v -o system_heaps -b HOL
    '';
  
  
negative.code:     substituteInPlace lib/Tools/env \
        --replace /usr/bin/env ${coreutils}/bin/env
  
      substituteInPlace src/Tools/Setup/src/Environment.java \
        --replace 'cmd.add("/usr/bin/env");' "" \
        --replace 'cmd.add("bash");' "cmd.add(\"$SHELL\");"
  
      rm -r heaps
    '' + (if ! stdenv.isLinux then "" else ''
      arch=${if stdenv.hostPlatform.system == "x86_64-linux" then "x86_64-linux" else "x86-linux"}
  