2007-12-20 Kieran Mansley (based on patch from Per-Henrik Lundbolm)

* tcp.c, tcp_in.c, tcp_out.c, tcp.h: fix bug #20199 (better handling
    of silly window avoidance and prevent lwIP from shrinking the window)

src/include/lwip/tcp.h

@@ -281,7 +281,8 @@ struct tcp_pcb {
   /* receiver variables */
   u32_t rcv_nxt;   /* next seqno expected */
   u16_t rcv_wnd;   /* receiver window */
-  
+  u16_t rcv_ann_wnd; /* announced receive window */
+
   /* Timers */
   u32_t tmr;
   u8_t polltmr, pollinterval;