Add missing <malloc.h> and <string.h> includes.

Change-Id: Ia41756e607663d056e7d2fdd7ecbec7e5841a913
diff --git a/libnetutils/packet.c b/libnetutils/packet.c
index a878dd3..cd26d05 100644
--- a/libnetutils/packet.c
+++ b/libnetutils/packet.c
@@ -15,6 +15,7 @@
  */
 
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 #include <sys/uio.h>
 #include <sys/socket.h>