anchor.diff: -{ fetchurl, stdenv, cmake, ruby }:
  +{ fetchurl, stdenv, cmake, perl, ruby }:
   
   stdenv.mkDerivation rec {
  -  name = "simgrid-3.4.1";
  +  name = "simgrid-3.5";
   
     src = fetchurl {
  -    url = "https://gforge.inria.fr/frs/download.php/26944/${name}.tar.bz2";
  -    sha256 = "acd2bb2c1abf59e9b190279b1c38582b7c1edd4b6ef4c6a9b01100740f1a6b28";
  +    url = "https://gforge.inria.fr/frs/download.php/28017/${name}.tar.gz";
  +    sha256 = "1vd4pvrcyii1nfwyca3kpbwshbc965lfpn083zd8rigg6ydchq8y";
     };
   
     /* FIXME: Ruby currently disabled because of this:
  
positive.code: 
    makeFlags = "VERBOSE=1";
  
    patchPhase =
      '' for i in "src/smpi/"*
         do
           sed -i "$i" -e's|/bin/bash|/bin/sh|g'
         done
      '';
  
    installPhase = "make install-simgrid";
  
    # Fixing the few tests that fail is left as an exercise to the reader.
    doCheck = false;
  
negative.code:      ld: cannot find -lruby-1.8.7-p72
  
     */
    buildInputs = [ cmake perl /* ruby */ ];
  
    preConfigure =
      # Make it so that libsimgrid.so will be found when running programs from
  