He says he wraps everything he uses in the standard library; "this tends to make my code idiosyncratic." At some Usenix, someone once summed it up to me as "It is the most beautiful code that is completely unmodifiable." Seemed appropriate. (Compare to procmail, where the quote was "seen the source? Gaah, my eyes are melting.")
I enjoyed watching this, thanks. I agree with the other comment "what, nothing about security?" Sendmail did enable the first Internet worm :)