OTP feature for /bin/login

[Guylhem]

Hello

I have prepared a OTP implementation for /bin/login, where a password
can optionally be replaced by an MOTP (md5 of epoch+pin+shared secret)
if ENABLE_FEATURE_LOGINOTP is defined.

This could be useful for example when using telnetd. The code can
easily be tweaked to support other things besides MOTP.

Shall I just post the code on the list? (it's a full replacement of
correct_password.c, GPLv2)

Guylhem