anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "sundials";
  -  version = "5.3.0";
  +  version = "5.6.1";
   
     buildInputs = [
       python
  
positive.code: 
    src = fetchurl {
      url = "https://computation.llnl.gov/projects/${pname}/download/${pname}-${version}.tar.gz";
      sha256 = "19xwi7pz35s2nqgldm6r0jl2k0bs36zhbpnmmzc56s1n3bhzgpw8";
    };
  
    patches = [
      (fetchurl {
        # https://github.com/LLNL/sundials/pull/19
        url = "https://github.com/LLNL/sundials/commit/1350421eab6c5ab479de5eccf6af2dcad1eddf30.patch";
        sha256 = "0g67lixp9m85fqpb9rzz1hl1z8ibdg0ldwq5z6flj5zl8a7cw52l";
      })
    ];
  
    cmakeFlags = [
      "-DEXAMPLES_INSTALL_PATH=${placeholder "out"}/share/examples"
    ] ++ stdenv.lib.optionals (lapackSupport) [
      "-DLAPACK_ENABLE=ON"
      "-DLAPACK_LIBRARIES=${lapack}/lib/liblapack${stdenv.hostPlatform.extensions.sharedLibrary}"
    ] ++ stdenv.lib.optionals (kluSupport) [
      "-DKLU_ENABLE=ON"
      "-DKLU_INCLUDE_DIR=${suitesparse.dev}/include"
      "-DKLU_LIBRARY_DIR=${suitesparse}/lib"
    ] ++ stdenv.lib.optionals (lapackSupport && !lapack.isILP64) [
      # Use the correct index type according to lapack which is supposed to be
      # the same index type compatible with blas, thanks to the assertion of
      # buildInputs
      "-DSUNDIALS_INDEX_TYPE=int32_t"
    ]
    ;
  
    doCheck = true;
  
negative.code: { stdenv
  , cmake
  , fetchurl
  , fetchpatch
  , python
  , blas
  , lapack
  