anchor.diff:  { stdenv, fetchurl, fetchFromGitHub, cmake, pkgconfig
   , cudatoolkit, opencl-clhpp, ocl-icd, fftw, fftwFloat, mkl
   , blas, openblas, boost, mesa, libGLU_combined
  -, freeimage, python
  +, freeimage, python, clfft, clblas
  +, doxygen, buildDocs ? false
   }:
   
   let
  +  strOnLinux = stdenv.lib.optionalString stdenv.isLinux;
  +
  +in stdenv.mkDerivation rec {
  +  pname = "arrayfire";
     version = "3.6.4";
  -
  -  clfftSource = fetchFromGitHub {
  -    owner = "arrayfire";
  -    repo = "clFFT";
  -    rev = "16925fb93338b3cac66490b5cf764953d6a5dac7";
  -    sha256 = "0y35nrdz7w4n1l17myhkni3hwm37z775xn6f76xmf1ph7dbkslsc";
  -    fetchSubmodules = true;
  -  };
  -
  -  clblasSource = fetchFromGitHub {
  -    owner = "arrayfire";
  -    repo = "clBLAS";
  -    rev = "1f3de2ae5582972f665c685b18ef0df43c1792bb";
  -    sha256 = "154mz52r5hm0jrp5fqrirzzbki14c1jkacj75flplnykbl36ibjs";
  -    fetchSubmodules = true;
  -  };
  -
  -  cl2hppSource = fetchurl {
  -    url = "https://github.com/KhronosGroup/OpenCL-CLHPP/releases/download/v2.0.10/cl2.hpp";
  -    sha256 = "1v4q0g6b6mwwsi0kn7kbjn749j3qafb9r4ld3zdq1163ln9cwnvw";
  -  };
  -
  -in stdenv.mkDerivation {
  -  pname = "arrayfire";
  -  inherit version;
   
     src = fetchurl {
       url = "http://arrayfire.com/arrayfire_source/arrayfire-full-${version}.tar.bz2";
  
positive.code:   nativeBuildInputs = [
      cmake
      pkgconfig
    ];
  
    buildInputs = [
  
negative.code:     "-DAF_BUILD_OPENCL=OFF"
      "-DAF_BUILD_EXAMPLES=OFF"
      "-DBUILD_TESTING=OFF"
      (strOnLinux "-DCMAKE_LIBRARY_PATH=${cudatoolkit}/lib/stubs")
    ];
  
    patches = [ ./no-download.patch ];
  
    postPatch = ''
      mkdir -p ./build/third_party/clFFT/src
      cp -R --no-preserve=mode,ownership ${clfft.src}/ ./build/third_party/clFFT/src/clFFT-ext/
      mkdir -p ./build/third_party/clBLAS/src
      cp -R --no-preserve=mode,ownership ${clblas.src}/ ./build/third_party/clBLAS/src/clBLAS-ext/
      mkdir -p ./build/include/CL
      cp -R --no-preserve=mode,ownership ${opencl-clhpp}/include/CL/cl2.hpp ./build/include/CL/cl2.hpp
    '';
  
    preBuild = strOnLinux ''
      export CUDA_PATH="${cudatoolkit}"
    '';
  
  