cmake: cocoa video backend needs IOKit framework

Fixes libsdl-org/SDL#11628

cmake/sdlchecks.cmake

@@ -629,6 +629,7 @@ macro(CheckCOCOA)
     endif()
     if(HAVE_COCOA)
       sdl_glob_sources("${SDL3_SOURCE_DIR}/src/video/cocoa/*.m")
+      set(SDL_FRAMEWORK_IOKIT 1)
       set(SDL_VIDEO_DRIVER_COCOA 1)
       set(HAVE_SDL_VIDEO TRUE)
     endif()