anchor.diff: -{ stdenv, fetchurl, python, cairomm, sparsehash, pycairo, autoreconfHook
  +{ fetchurl, python, cairomm, sparsehash, pycairo, autoreconfHook
   , pkg-config, boost, expat, scipy, cgal, gmp, mpfr
   , gobject-introspection, pygobject3, gtk3, matplotlib, ncurses
   , buildPythonPackage
  
positive.code:   ];
  
    enableParallelBuilding = false;
  }
  
negative.code: buildPythonPackage rec {
    pname = "graph-tool";
    format = "other";
    version = "2.30";
  
    src = fetchurl {
      url = "https://downloads.skewed.de/graph-tool/graph-tool-${version}.tar.bz2";
      sha256 = "1gy8xhwfms0psdji7vzqjbzj3l0k743aw20db27zxyq89cvz6g42";
    };
  
    configureFlags = [
  