[tz] attic data for the tz database

[Paul Eggert]

On 08/29/2013 09:36 AM, Paul_Koning at Dell.com wrote:

> It's a pretty easy addition to "zic" which I implemented in the
> version we use internally for the products I work on, exactly for
> the reason you mention.

Thanks, is that code something that you and your company would donate
to the public domain?  If so, it could save us some work.

How does the extension choose which of the alternate pre-1970 (or
whatever) histories to use?  For example, suppose America/Toronto
and America/Montreal are the same after 1970, so zic makes them
links.  Which pre-1970 history does it use, Toronto's or Montreal's?