[tz] tzdist and tz at iana

[Paul Eggert]

On 09/07/2016 12:07 PM, Paul.Koning at dell.com wrote:
> you could create a history from the entire set of archived tzdata* files.

Although we could do that (modulo the missing tarballs), the story's 
more complicated because we have two histories: the archived tarballs 
dating back to 1993, and the Git-based history dating back to 1984 
(pre-2012 history was originally in SCCS form). The Git-based history is 
more detailed, as it records each commit whereas the tarballs merely 
record the (much rarer) releases.

I would rather rely on the Git-based history, as it contains more 
information and it already exists. A downside is that nobody has 
correlated the Git-based history to the tarball history for releases 
before 2012e. (I tried, but ran into glitches and gave up.) Another 
downside is that minor details in older tarballs (e.g., file timestamps) 
are missing from or disagree with the Git-based history. But we can 
leave these less-pressing matters for some software historian of the future.