[tz] [PATCH] New file 'pre1970' for zones that differ only in pre-1970 time stamps.

[Zefram]

I wrote:
>                  Next up is use of tzwinnow in tzselect, which is the
>point at which we start to get a tangible benefit, so that's probably
>when I should start actually posting the patches.

Now implemented this.  Interesting discovery: this is actually the
most complex place to apply winnowing.  It's not just a matter of
making links: the region descriptions in zone.tab have to be merged,
and doing that in a way that produces legible results takes some effort.
I'm happy with the results I'm getting.

OK, patches.  You can pull the changes from my git repo,
<git://git.fysh.org/zefram/tz.git> branch zefram/winnow.  It's based on
Eggert's current master branch.  Unfortunately the first patch, which
adds the population data, is a bit big for the mailing list:

$ wc 00*
  4068  25639 172653 0001-add-Wikipedia-URLs-and-population-data.patch
   311   1739  11259 0002-generate-file-of-normalised-population-figures.patch
   276   1539   9871 0003-restore-the-rest-of-the-pre-1970-data.patch
   919   4059  24752 0004-new-program-tzwinnow.patch
   427   2441  17202 0005-optionally-winnow-zone-list-in-tzselect.patch
  6001  35417 235737 total

So I won't post the patches here unless instructed.

The third patch is optional.  The other four are sequentially
interdependent.

-zefram