[lwIP] Remove some default setting; User can re-define these settings or use the default setting in lwip opts.h file

Author: BernardXiong

components/net/lwip-1.4.1/src/lwipopts.h

@@ -123,17 +123,20 @@
 #define MEMP_NUM_TCP_SEG            TCP_SND_QUEUELEN
 #endif
 
-/* The following four are used only with the sequential API and can be
-   set to 0 if the application only will use the raw API. */
+/*
+ * You can re-define following setting in rtcofnig.h to overwrite the default 
+ * setting in the lwip opts.h 
+ */
 /* MEMP_NUM_NETBUF: the number of struct netbufs. */
-#define MEMP_NUM_NETBUF             2
+// #define MEMP_NUM_NETBUF             2
 /* MEMP_NUM_NETCONN: the number of struct netconns. */
-#define MEMP_NUM_NETCONN            4
+// #define MEMP_NUM_NETCONN            4
+
 /* MEMP_NUM_TCPIP_MSG_*: the number of struct tcpip_msg, which is used
    for sequential API communication and incoming packets. Used in
    src/api/tcpip.c. */
-#define MEMP_NUM_TCPIP_MSG_API      16
-#define MEMP_NUM_TCPIP_MSG_INPKT    16
+// #define MEMP_NUM_TCPIP_MSG_API      16
+// #define MEMP_NUM_TCPIP_MSG_INPKT    16
 
 /* ---------- Pbuf options ---------- */
 /* PBUF_POOL_SIZE: the number of buffers in the pbuf pool. */