From aa0317bdb952935f005e46cce8950798821ad791 Mon Sep 17 00:00:00 2001
From: Dong Heng <dongheng@espressif.com>
Date: Tue, 18 Sep 2018 15:54:32 +0800
Subject: [PATCH] fix(lwip): Fix compiling error when disable UDP sync

---
 components/lwip/port/esp8266/netif/ethernetif.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/components/lwip/port/esp8266/netif/ethernetif.c b/components/lwip/port/esp8266/netif/ethernetif.c
index 1c3edf90..42dbef09 100644
--- a/components/lwip/port/esp8266/netif/ethernetif.c
+++ b/components/lwip/port/esp8266/netif/ethernetif.c
@@ -238,7 +238,9 @@ static int low_level_send_cb(esp_aio_t* aio)
 
     pbuf_free(pbuf);
 
+#if ESP_UDP
     udp_sync_trigger();
+#endif
 
     return 0;
 }