fix HAVE_SDL_VIDEO flag of CMakeLists.txt [IOS OR TVOS]

CMakeLists.txt

@@ -1988,6 +1988,7 @@ elseif(APPLE)
       set(SDL_IPHONE_LAUNCHSCREEN 1)
       file(GLOB UIKITVIDEO_SOURCES ${SDL2_SOURCE_DIR}/src/video/uikit/*.m)
       set(SOURCE_FILES ${SOURCE_FILES} ${UIKITVIDEO_SOURCES})
+      set(HAVE_SDL_VIDEO TRUE)
     else()
       CheckCOCOA()
       if(SDL_OPENGL)