Fix vsync initialization

main/main.cpp

@@ -867,6 +867,8 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 	OS::get_singleton()->_allow_layered = GLOBAL_DEF("display/window/allow_per_pixel_transparency", false);
 
 	video_mode.use_vsync = GLOBAL_DEF("display/window/vsync/use_vsync", true);
+	OS::get_singleton()->_use_vsync = video_mode.use_vsync;
+
 	video_mode.layered = GLOBAL_DEF("display/window/per_pixel_transparency", false);
 	video_mode.layered_splash = GLOBAL_DEF("display/window/per_pixel_transparency_splash", false);