> it's not just me that has written lines slightly too long.

That's right, lots of people are doing it, and it makes more busywork when 
cleaning up ChangeLogs, which sucks.  I don't have much faith in fixing this 
automagically, as a lot could go wrong.

There's a much simpler fix (see attached) but Stefan nixed it (see 
<http://lists.gnu.org/archive/html/emacs-devel/2014-12/msg01640.html>) for 
reasons that I don't follow.  Perhaps we could take another run at him and he'll 
relent this time.

Another possibility is that we set the tab-width in ChangeLog files to 2, so 
that 78-character log lines fit in ChangeLog files when displayed via Emacs. 
(I'm *sure* nobody would complain about *that*. :-)

But really, it'd be simpler to shrink that "78" back to "72".