fix lwip 1.4.1 compiling error when enable component init

bsp/lpc176x/rtconfig.h

@@ -142,7 +142,7 @@
 // <integer name="RT_LWIP_TCP_PCB_NUM" description="Maximal number of simultaneously active TCP connections" default="5" />
 #define RT_LWIP_TCP_PCB_NUM	3
 // <integer name="RT_LWIP_TCP_SND_BUF" description="TCP sender buffer size" default="8192" />
-#define RT_LWIP_TCP_SND_BUF	2048
+#define RT_LWIP_TCP_SND_BUF	(2 * TCP_MSS)
 // <integer name="RT_LWIP_TCP_WND" description="TCP receive window" default="8192" />
 #define RT_LWIP_TCP_WND	2048
 // <bool name="RT_LWIP_SNMP" description="Enable SNMP protocol" default="false" />

components/net/lwip-1.4.1/src/arch/sys_arch.c

@@ -139,7 +139,7 @@ int lwip_system_init(void)
     {
         LWIP_ASSERT("Failed to create semaphore", 0);
 
-        return;
+        return -1;
     }
 
     tcpip_init(tcpip_init_done_callback, (void *)&done_sem);
@@ -149,7 +149,7 @@ int lwip_system_init(void)
     {
         rt_sem_detach(&done_sem);
 
-        return;
+        return -1;
     }
     rt_sem_detach(&done_sem);
 

components/net/lwip-1.4.1/src/include/netif/ethernetif.h

@@ -30,6 +30,6 @@ rt_err_t eth_device_init(struct eth_device * dev, char *name);
 rt_err_t eth_device_init_with_flag(struct eth_device *dev, char *name, rt_uint8_t flag);
 rt_err_t eth_device_linkchange(struct eth_device* dev, rt_bool_t up);
 
-void eth_system_device_init(void);
+int eth_system_device_init(void);
 
 #endif /* __NETIF_ETHERNETIF_H__ */

components/net/lwip-1.4.1/src/netif/ethernetif.c

@@ -350,7 +350,7 @@ static void eth_rx_thread_entry(void* parameter)
     }
 }
 
-void eth_system_device_init()
+int eth_system_device_init(void)
 {
     rt_err_t result = RT_EOK;
 
@@ -382,6 +382,8 @@ void eth_system_device_init()
 
     result = rt_thread_startup(&eth_tx_thread);
     RT_ASSERT(result == RT_EOK);
+	
+	return 0;
 }
 INIT_DEVICE_EXPORT(eth_system_device_init);