opensubdiv: fix darwin build

pkgs/development/libraries/opensubdiv/default.nix

@@ -1,6 +1,7 @@
 { lib, stdenv, fetchurl, fetchFromGitHub, cmake, pkgconfig, xorg, libGLU
 , libGL, glew, ocl-icd, python3
 , cudaSupport ? false, cudatoolkit
+, darwin
 }:
 
 stdenv.mkDerivation rec {
@@ -17,17 +18,21 @@ stdenv.mkDerivation rec {
   outputs = [ "out" "dev" ];
 
   buildInputs =
-    [ cmake pkgconfig libGLU libGL ocl-icd python3
+    [ cmake pkgconfig libGLU libGL python3
       # FIXME: these are not actually needed, but the configure script wants them.
       glew xorg.libX11 xorg.libXrandr xorg.libXxf86vm xorg.libXcursor
       xorg.libXinerama xorg.libXi
     ]
+    ++ lib.optional (!stdenv.isDarwin) ocl-icd
+    ++ lib.optionals stdenv.isDarwin (with darwin.apple_sdk.frameworks; [OpenCL Cocoa CoreVideo IOKit AppKit AGL ])
     ++ lib.optional cudaSupport cudatoolkit;
 
   cmakeFlags =
     [ "-DNO_TUTORIALS=1"
       "-DNO_REGRESSION=1"
       "-DNO_EXAMPLES=1"
+      "-DNO_METAL=1" # don’t have metal in apple sdk
+    ] ++ lib.optionals (!stdenv.isDarwin) [
       "-DGLEW_INCLUDE_DIR=${glew.dev}/include"
       "-DGLEW_LIBRARY=${glew.dev}/lib"
     ] ++ lib.optionals cudaSupport [
@@ -42,7 +47,7 @@ stdenv.mkDerivation rec {
   meta = {
     description = "An Open-Source subdivision surface library";
     homepage = http://graphics.pixar.com/opensubdiv;
-    platforms = lib.platforms.linux;
+    platforms = lib.platforms.unix;
     maintainers = [ lib.maintainers.eelco ];
     license = lib.licenses.asl20;
   };