input: give up on the input stream only after millions of errors

This mitigates a problem seen sometimes among the Red Hat crash reports:
somehow wgetch() keeps returning ERR, as if it were in nodelay mode.
(I've seen this happen once after nano came out of suspension.)

Using a much larger error-count value gives the user a few seconds
to type something and hopefully get out of the error condition.

src/winio.c

@@ -233,11 +233,11 @@ void read_keys_from(WINDOW *win)
 			}
 		}
 #endif
-		/* When we've failed to get a keycode over a hundred times in a row,
+		/* When we've failed to get a keycode millions of times in a row,
 		 * assume our input source is gone and die gracefully.  We could
 		 * check if errno is set to EIO ("Input/output error") and die in
 		 * that case, but it's not always set properly.  Argh. */
-		if (input == ERR && ++errcount == 123)
+		if (input == ERR && ++errcount == 12345678)
 			die(_("Too many errors from stdin\n"));
 	}