[PATCH] Fix multiple minor tzset glitches [BZ #24004]

[Paul Eggert]

On 4/10/19 6:18 AM, Carlos O'Donell wrote:
> I think there *have* to be ways in which this data can be dynamically
> updated without a huge performance penalty. 

What ways are those, though? It's not like the penalty is zero.

One possible compromise would be for localtime to poll, and for
localtime_r to not poll (you must call tzset to poll), and tell people
"if you want performance, use localtime_r". That might hit a sweet spot
of doing polling for naive programs where performance matters, and
giving higher performance for applications that care about timestamp
performance.