Barry, that comment belongs in the code, not in the checkin msg.
    The code *used* to do this correctly (as you well know, since you
    & I went thru considerable pain to fix this the first time).
    However, because the *reason* for the convolution wasn't recorded
    in the code as a comment, somebody threw it all away the first
    time it got reworked.

    c-code-isn't-often-self-explanatory-ly y'rs  - tim

default_3way_compare(): Stick the checkin message from 2.110 in a
comment.