anchor.diff:  { fetchurl, stdenv, unzip, libtool }:
   
   stdenv.mkDerivation rec {
  -  name = "crypto++-5.6.0";
  +  name = "crypto++-5.6.1";
   
     src = fetchurl {
  -    url = "mirror://sourceforge/cryptopp/cryptopp560.zip";
  -    sha256 = "1icbk50mr1sqycqbxbqg703m8aamz23ajgl22ychxdahz2sz08mm";
  +    url = "mirror://sourceforge/cryptopp/cryptopp561.zip";
  +    sha256 = "0s7jhvnfihikqp1iwpdz03fad62xkjxci6jiahrh6f3sn664vrwq";
     };
   
     patches = [ ./pic.patch ]
  
positive.code:   '';
  
    cxxflags = if stdenv.isi686 then "-march=i686" else
               if stdenv.isx86_64 then "-march=nocona" else
               "";
  
    configurePhase = ''
  
negative.code:       -e '/^CXXFLAGS =/s|-g -O2|-O3|'
    '';
  
    # I add what 'enableParallelBuilding' would add to the make call,
    # if we were using the generic build phase.
    buildPhase = ''
      make PREFIX="$out" all libcryptopp.so -j$NIX_BUILD_CORES -l$NIX_BUILD_CORES
    '';
  
    # TODO: Installing cryptotest.exe doesn't seem to be necessary. We run
  