anchor.diff:          sha256 = "13rb2v2872jmvzcqm4fqsvhry0j2r5cn4lqql4wpqbl1yia2pph6";
         });
   
  -  buildInputs = if stdenvNoCC.isDarwin then [ undmg ] else [ rpmextract ];
  +  nativeBuildInputs = if stdenvNoCC.isDarwin
  +    then
  +      [ undmg
  +        darwin.cctools
  +      ]
  +    else
  +      [ rpmextract ];
   
     buildPhase = if stdenvNoCC.isDarwin then ''
         for f in Contents/Resources/pkg/*.tgz; do
  
positive.code:     platforms = [ "x86_64-linux" "x86_64-darwin" ];
      maintainers = [ maintainers.bhipple ];
    };
  }
  
negative.code: { stdenvNoCC, writeText, fetchurl, rpmextract, undmg, darwin }:
  /*
    For details on using mkl as a blas provider for python packages such as numpy,
    numexpr, scipy, etc., see the Python section of the NixPkgs manual.
  */
  stdenvNoCC.mkDerivation (rec {
    name = "mkl-${version}";
    version = "${date}.${rel}";
    date = "2019.3";
  