bug#19113: Generate a ChangeLog file from commit logs

[Paul Eggert]

Glenn Morris wrote:
> I would like to see people get at least one week's notice, since this
> changes a decades-old convention. This bug report doesn't count as
> notice. So Jan 21 is almost too soon...

Yes, I'll change the date to give people a week at least.

> To avoid confusion, does emacs-24 need to merged to trunk just before
> this change?

I was planning to do a merge, yes.  My thought was to install the changes in 
emacs-24 and then skip them when merging to master, as there's a separate set of 
changes prepared for master.