extra control characters in panic messages

I noticed a few panic messages contained newlines, and one included a naked
carriage return.  panic() adds a newline itself, and also generally ensures
the message will be on a new line (the initial "oops" ensures the message
itself will be on a new lines).  This patch removes the unneeded characters.

win/X11/winmap.c

@@ -1654,7 +1654,7 @@ x_event(exit_condition)
 		}
 		break;
 	    default:
-		panic("x_event: unknown exit condition %d\n", exit_condition);
+		panic("x_event: unknown exit condition %d", exit_condition);
 		break;
 	}
     } while (keep_going);