[tz] Magallanes region from Chile will keep DST all year round

[Paul Eggert]

Deborah Goldsmith wrote:
> Distributing an intermediate version from the GitHub repository is problematic because calling it either 2016j or 2017a are both incorrect.

It's common for distributors to tailor the database and to append a suffix to 
reflect any changes that they make downstream. For example, on the machine I'm 
typing this email message on, the version is '2016j-0ubuntu0.16.04'. On my 
desktop at work, the version is '2016j-1.fc25'. The tz development repository 
uses version numbers like '2016j-38-g46c2bbf' (the current development version). 
Apple could use version numbers like '2016j-apple1', or if Apple merely wants to 
clone the development repository then it could use the development repository's 
version number.

It'd be a bit of a stretch to expect every platform to have the same data and 
version number, as there are too many options. For example, Fedora doesn't 
install the factory and systemv entries, and FreeBSD doesn't install the 
backward entries.

> Downstream providers would have to make up an identifier which wouldn’t be cross-platform, and could cause problems with software that wasn’t expecting it.

As there is no portable way to get a version number from the data, I'd be 
surprised if cross-platform software relied on a tzdb version number.