anchor.diff:      doCheck = false;
     };
   
  +  enableParallelBuilding = true;
  +
     doCheck = true;
   
     meta = {
  
positive.code:     ''
        --with-store-dir=${storeDir} --localstatedir=${stateDir}
        --with-bzip2=${bzip2} --with-sqlite=${sqlite}
        --disable-init-state
        --enable-gc
        CFLAGS=-O3 CXXFLAGS=-O3
  
negative.code: { stdenv, fetchurl, perl, curl, bzip2, sqlite, openssl ? null
  , pkgconfig, boehmgc, perlPackages
  , storeDir ? "/nix/store"
  , stateDir ? "/nix/var"
  }:
  
  stdenv.mkDerivation rec {
    name = "nix-1.0pre26784";
  
    src = fetchurl {
      url = "http://hydra.nixos.org/build/1041231/download/4/${name}.tar.bz2";
      sha256 = "33711d31b25b99f0ee06ad093332f71b2be5abdbb52d5eed77c42d7e24ad3765";
    };
  
    buildNativeInputs = [ perl pkgconfig ];
  