[tz] zdump with version 1 files

[Paul Eggert]

On 3/22/20 9:52 AM, Brian Inglis wrote:

>> Perhaps it was true long ago but
>> became false when Android started supporting 64-bit CPUs; a bit of Googling
>> suggests this occurred with Android 5.0 Lollipop (2014).

> https://android.googlesource.com/platform/system/timezone/+/refs/heads/master/update-tzdata.py#134

>    # zic
>    print('Building zic...')
>    # VERSION_DEPS= is to stop the build process looking for files that might not
>    # be present across different versions.
>    subprocess.check_call(['make', '-C', zic_build_dir, 'zic'])

Thanks for the pointer. If I understand the code aright, they now generate 
version 2 or 3 TZif data. It is a little odd, though, since the comment about 
VERSION_DEPS does not match the code. Perhaps someone who's actually built AOSP 
can verify. Anyway, for now I'll guess that Android 5.0 Lollipop (2014) and 
later do not use version 1 format.

statcounter.com estimates that 2.08% of Android devices are still running KitKat 
(2013), the release before Lollipop. If you add in the even-older releases I'd 
guess about 3% of Android devices predate Lollipop. As far as I know nobody 
supports these older devices and they are not getting tzdata updates.

So it appears that version 1 TZif format is truly dead, and we needn't worry 
about it.