anchor.diff:    in
       stdenv.mkDerivation rec {
         pname = "opencl-clang";
  -      version = "unstable-2019-08-16";
  +      version = "unstable-2021-06-22";
   
         inherit passthru;
   
         src = fetchFromGitHub {
           owner = "intel";
           repo = "opencl-clang";
  -        rev = "94af090661d7c953c516c97a25ed053c744a0737";
  -        sha256 = "05cg89m62nqjqm705h7gpdz4jd4hiczg8944dcjsvaybrqv3hcm5";
  +        rev = "fd68f64b33e67d58f6c36b9e25c31c1178a1962a";
  +        sha256 = "sha256-q1YPBb/LY67iEuQx1fMUQD/I7OsNfobW3yNfJxLXx3E=";
         };
   
         patches = [
  
positive.code:     });
  
    passthru = rec {
  
      libclang = addPatches "clang" llvmPkgs.libclang;
  
      clang-unwrapped = libclang.out;
  
negative.code:     patchesOut = stdenv.mkDerivation rec {
        pname = "opencl-clang-patches";
        inherit (library) version src patches;
        # Clang patches assume the root is the llvm root dir
        # but clang root in nixpkgs is the clang sub-directory
        postPatch = ''
          for filename in patches/clang/*.patch; do
            substituteInPlace "$filename" \
              --replace "a/clang/" "a/" \
              --replace "b/clang/" "b/"
          done
        '';
  
        installPhase = ''
          [ -d patches ] && cp -r patches/ $out || mkdir $out
          mkdir -p $out/clang $out/llvm
        '';
      };
    };
  
    library = let
  