Index: tcp/tcp-full.h
--- tcp/tcp-full.h.orig
+++ tcp/tcp-full.h
@@ -223,8 +223,8 @@ class FullTcpAgent : public TcpAgent { (protected)
 	DelAckTimer delack_timer_;	// other timers in tcp.h
 	void cancel_timers();		// cancel all timers
 	void prpkt(Packet*);		// print packet (debugging helper)
-	char *flagstr(int);		// print header flags as symbols
-	char *statestr(int);		// print states as symbols
+	const char *flagstr(int);	// print header flags as symbols
+	const char *statestr(int);	// print states as symbols
 
 	/*
 	* the following are part of a tcpcb in "real" RFC793 TCP