[Realtek][RTL8721CSM] net/netmgr/netdev_lwip.c : Fix Macros in netdev_lwip.c
1st commit fix of netdev_lwip.c Macros, _netif_loop_output_ipv4 and _netif_loop_output_ipv6 are not defined if LWIP_HAVE_LOOPIF is 0.
@@ -618,12 +618,14 @@ static err_t _netif_loopif_init(struct netif *netif)
netif->name[0] = 'l';
netif->name[1] = 'o';
+#if LWIP_HAVE_LOOPIF
#if LWIP_IPV4
netif->output = _netif_loop_output_ipv4;
#endif
#if LWIP_IPV6
netif->output_ip6 = _netif_loop_output_ipv6;
#endif
+#endif
#if LWIP_LOOPIF_MULTICAST
netif->flags |= NETIF_FLAG_IGMP;
#endif
