[tz] Add new timezone for Hanoi Capital, Vietnam

[Guy Harris]

On Feb 18, 2019, at 9:47 PM, Kevin Lyda <kevin at ie.suberic.net> wrote:

> By populations...
> 
> % ls /usr/share/zoneinfo/America/|wc -l
>     144
> % ls /usr/share/zoneinfo/Asia/|wc -l
>      99
> 
> Asia has around 59% of the world's population in 48 countries; the
> Americas have 14% in 35 countries. Seems quite possible there's scope
> to improve things in Asia.

Yes, Asia could split itself into more countries, for example....

Or perhaps Asian countries are not as crazy as Western Hemisphere countries about doing silly things with summer/daylight savings time rules:

	$ egrep '^Rule' northamerica southamerica | wc -l
	     610
	$ egrep '^Rule' asia | wc -l
	     463

or about having multiple zones per country (China has two, the contiguous 48 states of the US has four plus various random places that don't do DST):

	$ egrep '^Zone' northamerica southamerica | wc -l
	     140
	$ egrep '^Zone' asia | wc -l
	      61

I.e., having a lot of stuff in the tzdb for your continent could be considered a bug rather than a feature; that is *not* necessarily a sign that the tzdb doesn't do a good enough job of covering your continent, it may be just a sign that your continent doesn't impose as much of a burden on the tzdb....