Add version check to I_OpenURL

src/sdl/i_system.cpp

@@ -1024,7 +1024,11 @@ boolean I_HasOpenURL()
 
 void I_OpenURL(const char *data)
 {
+	#if (SDL_VERSION_ATLEAST(2, 0, 14))
 		SDL_OpenURL(data);
+	#else
+		return;
+	#endif
 }
 
 //