Our FreeBSD libc based libc defines SOL_SOCKET as 0xffff. We change
lwip's definition from 0xfff to match ours. This prevents us from
converting the level when we call {g,s}etsockopt.

--- a/src/include/lwip/sockets.h
+++ b/src/include/lwip/sockets.h
@@ -131,7 +131,7 @@ struct linger {
 /*
  * Level number for (get/set)sockopt() to apply to socket itself.
  */
-#define  SOL_SOCKET  0xfff    /* options for socket level */
+#define  SOL_SOCKET  0xffff   /* options for socket level */
 
 
 #define AF_UNSPEC       0