opencolorio2: Refactor dependencies

Python bindings and utility applications can now be disabled if desired.
GPU rendering is always enabled.

pkgs/development/libraries/opencolorio/default.nix

···
-{ stdenv, lib, fetchFromGitHub, cmake, expat, libyamlcpp, ilmbase, pystring, lcms2, python3Packages }:
+{
+  stdenv, lib, fetchFromGitHub,
+  cmake, expat, libyamlcpp, ilmbase, pystring, # Base dependencies
+
+  glew, freeglut, # Only required on Linux
+  Carbon, GLUT, Cocoa, # Only required on Darwin
+
+  pythonBindings ? true, # Python bindings
+  python3Packages,
+
+  buildApps ? true, # Utility applications
+  lcms2, openimageio2, openexr,
+}:
 
 with lib;
 
···
   };
 
   nativeBuildInputs = [ cmake ];
-  buildInputs = [ expat libyamlcpp ilmbase pystring lcms2 python3Packages.pybind11 ];
+  buildInputs = [ expat libyamlcpp ilmbase pystring ]
+    ++ lib.optionals stdenv.hostPlatform.isLinux [ glew freeglut ]
+    ++ lib.optionals stdenv.hostPlatform.isDarwin [ Carbon GLUT Cocoa ]
+    ++ lib.optionals pythonBindings [ python3Packages.python python3Packages.pybind11 ]
+    ++ lib.optionals buildApps [ lcms2 openimageio2 openexr ];
+
+    cmakeFlags = [ "-DOCIO_INSTALL_EXT_PACKAGES=NONE" ]
+    ++ lib.optional (!pythonBindings) "-DOCIO_BUILD_PYTHON=OFF"
+    ++ lib.optional (!buildApps) "-DOCIO_BUILD_APPS=OFF";
 
-  cmakeFlags = [ "-DOCIO_INSTALL_EXT_PACKAGES=NONE" ];
+  # TODO Investigate this: Python and GPU tests fail to load libOpenColorIO.so.2.0
+  # doCheck = true;
 
   meta = with lib; {
     homepage = "https://opencolorio.org";

pkgs/top-level/all-packages.nix

···
   openldap = callPackage ../development/libraries/openldap { };
 
   opencolorio1 = callPackage ../development/libraries/opencolorio/1.x.nix { };
-  opencolorio2 = callPackage ../development/libraries/opencolorio { };
+  opencolorio2 = callPackage ../development/libraries/opencolorio {
+    inherit (darwin.apple_sdk.frameworks) Carbon GLUT Cocoa;
+  };
   opencolorio = opencolorio1;
 
   opendmarc = callPackage ../development/libraries/opendmarc { };