anchor.diff:  assert useCurl -> (curl != null);
   
   stdenv.mkDerivation rec {
  -  name = "gnupg-2.0.19";
  +  name = "gnupg-2.0.20";
   
     src = fetchurl {
       url = "mirror://gnupg/gnupg/${name}.tar.bz2";
  -    sha256 = "08n636sfffs5qvg9ppiprvsh00q0dmdw425psg3m3nssja53m8pg";
  +    sha256 = "16mp0j5inrcqcb3fxbn0b3aamascy3n923wiy0y8marc0rzrp53f";
     };
   
     buildInputs = [ readline zlib libgpgerror libgcrypt libassuan libksba pth ]
  
positive.code:       S/MIME.
      '';
  
      homepage = http://gnupg.org/;
  
      license = "GPLv3+";
  
      maintainers = with stdenv.lib.maintainers; [ ludo urkud ];
  
      platforms = stdenv.lib.platforms.all;
    };
  }
  
negative.code:   doCheck = true;
  
    meta = {
      homepage = "http://gnupg.org/";
      description = "GNU Privacy Guard (GnuPG), GNU Project's implementation of the OpenPGP standard";
      license = stdenv.lib.licenses.gpl3Plus;
  
      longDescription = ''
        GnuPG is the GNU project's complete and free implementation of
  