anchor.diff:    configureScript = "./bootstrap.sh";
     configureFlags = "--with-icu=${icu} --with-python=${python}/bin/python";
   
  -  buildPhase = "./bjam -sEXPAT_INCLUDE=${expat}/include -sEXPAT_LIBPATH=${expat}/lib --layout=${finalLayout} variant=${variant} threading=${threading} link=${link} ${cflags} install";
  +  buildPhase = "./bjam -j$NIX_BUILD_CORES -sEXPAT_INCLUDE=${expat}/include -sEXPAT_LIBPATH=${expat}/lib --layout=${finalLayout} variant=${variant} threading=${threading} link=${link} ${cflags} install";
   
     installPhase = ":";
   }
  
positive.code:   };
  
    src = fetchurl {
      url = "mirror://sourceforge/boost/boost_1_43_0.tar.bz2";
      sha256 = "0831h19ph65r2rai6ipk5c2bx04af8q423mzr89fh454385i0krl";
    };
  
    buildInputs = [icu expat zlib bzip2 python];
  
negative.code: in
  
  stdenv.mkDerivation {
    name = "boost-1.44.0";
  
    meta = {
      homepage = "http://boost.org/";
  