Incorporate apple-specific OpenCL include directory from the other...

Incorporate apple-specific OpenCL include directory from the other FindOpenCL.cmake in the platforms/opencl CMakeLists.txt file.
TODO - in future use only one FindOpenCL.cmake file.

cmake_modules/FindOpenCL.cmake

@@ -11,7 +11,11 @@ if(ENV_OPENCL_DIR)
   endif("${CMAKE_SYSTEM_NAME}" MATCHES "Linux")
   find_library(OPENCL_LIBRARY NAMES OpenCL PATHS ${OPENCL_LIB_SEARCH_PATH} NO_DEFAULT_PATH)
 else(ENV_OPENCL_DIR)
+  if (APPLE)
+    find_path(OPENCL_INCLUDE_DIR NAMES OpenCL/cl.h)
+  else (APPLE)
     find_path(OPENCL_INCLUDE_DIR NAMES CL/cl.h)
+  endif(APPLE)
   find_library(OPENCL_LIBRARY NAMES OpenCL)
 endif(ENV_OPENCL_DIR)