Dependencies on C library memset() etc., so include <string.h>.

src/core/dhcp.c

@@ -67,6 +67,9 @@
  * to remove the DHCP client.
  *
  */
+ 
+#include <string.h>
+ 
 #include "lwip/stats.h"
 #include "lwip/mem.h"
 #include "lwip/udp.h"

src/core/mem.c

@@ -36,6 +36,7 @@
  *
  */
 
+#include <string.h>
 
 #include "lwip/arch.h"
 #include "lwip/opt.h"

src/core/raw.c

@@ -38,6 +38,8 @@
  *
  */
 
+#include <string.h>
+
 #include "lwip/opt.h"
 
 #include "lwip/def.h"

src/core/stats.c

@@ -30,6 +30,7 @@
  *
  */
 
+#include <string.h>
 
 #include "lwip/opt.h"
 

src/core/tcp.c

@@ -41,6 +41,8 @@
  *
  */
 
+#include <string.h>
+
 #include "lwip/opt.h"
 #include "lwip/def.h"
 #include "lwip/mem.h"

src/core/udp.c

@@ -42,6 +42,8 @@
  *
  */
 
+#include <string.h>
+
 #include "lwip/opt.h"
 
 #include "lwip/def.h"