File bash-4.1-intr.dif of Package bash.625

--- parse.y
+++ parse.y	2010-01-20 13:51:39.000000000 +0000
@@ -1434,10 +1434,11 @@ yy_readline_get ()
       					  current_readline_prompt : "");
 
       terminate_immediately = 0;
-      if (signal_is_ignored (SIGINT) == 0 && old_sigint)
+      if (signal_is_ignored (SIGINT) == 0)
 	{
 	  interrupt_immediately--;
-	  set_signal_handler (SIGINT, old_sigint);
+	  if (old_sigint)
+	    set_signal_handler (SIGINT, old_sigint);
 	}
 
 #if 0