Fix from Paul Breed:

* main.c (captured_main): Add a `break' after the case for 'b'.

gdb/main.c

@@ -397,6 +397,7 @@ extern int gdbtk_test (char *);
 	      else
 		baud_rate = i;
 	    }
+            break;
 	  case 'l':
 	    {
 	      int i;