When doing a silent old config, don't check if stdin was redirected. ct-ng doesn't use this feature, and even better yet, it makes explicit use of redirecting both stdin and stdout at aome moments.
1 This is NOT the official version of dialog. This version has been
2 significantly modified from the original. It is for use by the Linux
3 kernel configuration script. Please do not bother Savio Lam with
4 questions about this program.