Merge algorithms

[Stephen J. Turnbull]

Eli Zaretskii writes:

 > No, there will be no corruption, because when I merge from
 > mainline, I need to edit the logs anyway.

Eli, it's not about *you* Eli, it's about you Emacs developers, some
of whom are are far less careful than you Eli are.

I'm just saying that I think this heuristic is likely to cause
occasional hassles and ugliness, because the right way to use it is
far from obvious.  In ChangeLogs it's probably not a very big deal,
though.