[tz] zdump new option -i for easier-to-review output

[Paul Eggert]

Jon Skeet wrote:

> Is that due to dates past 2038, or something else?

Also dates before 1901 for 32-bit signed time_t, or before 1970 for unsigned 
time_t. I want the pre-1901 transitions to be checked, though, so I would rather 
stick with 64-bit signed time_t when generating the reference file.

Plus, on some platforms zdump uses CRLF instead of LF to terminate output lines. 
There may be other niggling things like that.

> I'd be testing something where time_t doesn't get involved at all, of
> course - an entirely different, non-C-based representation. That's the
> point of it, from my perspective.

Something with bignums, say? (Because 64-bit signed time_t doesn't suffice for 
simulations of proton decay in degenerate stars. See:

Adams FC. The future history of the universe. Cosmic Update. 2011-07-23. 
http://dx.doi.org/10.1007/978-1-4419-8294-0_3

:-)