message: Fix Apple link errors when disabling Vulkan
  Apple needs Cocoa and Quartz for Vulkan or OpenGL version
diff: @@ -26,13 +26,11 @@ elseif(APPLE)
  PRIVATE -lm
  PRIVATE -ldl)
  - if(ENABLE_VULKAN)
  find_library(COCOA_LIBRARY Cocoa)
  list(APPEND RDOC_LIBRARIES PRIVATE ${COCOA_LIBRARY})
  find_library(QUARTZCORE_LIBRARY QuartzCore)
  list(APPEND RDOC_LIBRARIES PRIVATE ${QUARTZCORE_LIBRARY})
  - endif()
  if(ENABLE_GL)
  find_library(OPENGL_LIBRARY OpenGL)
  