package-wide copyright year updates

[Joel E. Denny]

On some other GNU mailing list (I can't remember which), I recently 
noticed a discussion about a change in GNU's recommendation for copyright 
year updates.  Here's the new recommendation:

  To update the list of year numbers, add each year in which you have
  made nontrivial changes to the package. (Here we assume you're using a
  publicly accessible revision control server, so that every revision
  installed is also immediately and automatically published.) When you
  add the new year, it is not required to keep track of which files have
  seen significant changes in the new year and which have not. It is
  recommended and simpler to add the new year to all files in the
  package, and be done with it for the rest of the year.

I think this is a nice change.  I frequently forget to update copyright 
years when I write patches.  I don't like wasting time checking whether I 
need to update the year every time I write a patch.  I don't like the 
distraction when reading diffs.  Occasionally, I've noticed a cherry-pick 
that fails to update the year in the target branch because it was 
previously updated only in the source branch.  I'd be happy to be rid of 
all this hassle.

Does anyone object to adopting this policy for Bison?  If not, I'll follow 
with a patch to update the copyright year in every file in master, 
branch-2.5, and branch-2.4.2.

Akim, I'll be sure to wait for your opinion before proceeding.  If you 
want some time to consider this proposal, I'll be happy to wait a couple 
of weeks for your return.