fix ios compil

src/hello_imgui_demos/hello_manual_render/hello_manual_render.main.cpp

@@ -8,7 +8,7 @@ void Gui()
 };
 
 
-int main()
+int main(int , char *[])
 {
     // Run 2 applications, one after the other
     // to make sure that the manual render is working correctly and releasing resources