[Buildroot] [PATCH 2/2] package/tzdata: bump version to 2020f

[Alexandre Belloni <alexandre.belloni@bootlin.com>]

On 14/02/2021 21:35:43+0100, Yann E. MORIN wrote:
> On 2021-02-14 19:35 +0100, Romain Naour spake thusly:
> > Le 14/02/2021 ? 19:21, Alexandre Belloni a ?crit?:
> > > On 14/02/2021 17:34:47+0100, Peter Korsgaard wrote:
> > >> Ok, thanks. There was a report on IRC that timezones on uClibc were
> > >> broken as well because of an incompatibility between the new tzdata
> > >> files and tzdump.
> > > No, the issue is with zic that is not generating proper Tzif2 files (the
> > > tzif2 header is there twice).
> > The issue happen on Glibc toolchain.
> 
> The issues *also* happends on uClibc toolchains (as reported on IRC),
> and I suspect it also happens on musl toolchains (as it uses the same
> tzdata and zic as for glibc).
> 
> And Alexandre investigated quickly a few days ago, and reported on IRC
> (quoting):
> 
> 01:01 < abelloni> mcon: temporary workaround, you can revert 7868289fd53480201f8be7b72097246b7923611c.
> 01:02 < abelloni> y_morin: ^
> 01:02 < abelloni> y_morin: since the bump the zic output has two TZif2 headers, this breaks tzdump
> 01:03 < abelloni> maybe this also break glibc, I didn't check yet
> 
> So it looks like the duplicated header is causing issues everywhere...
> 
> > I added back the previous default zic format "fat" instead of "slim" [1] to pass
> > the test. The default format has been changed in 2020b release.
> > I'm not sure if we should keep the "fat" format...
> > [1] https://github.com/eggert/tz/commit/6ba6f2117b95eab345a7ed9159cef939e30c4cd3
> 
> From this, it looks like the 'fat' format is not 2038-safe, while the
> 'slim' one is.
> 
> To be noted: the glibc version used in thoses tests is 2.18, released in
> August 2013...
> 
> It seems the support for the slim format was only introduced with glibc
> 2.32. 2.31 has no mention of either slim or fat, while 2.32 mention
> both, as it synced with upstream tz 2020a; the previous sync was with
> 2018i...
> 
> So, what I suggest we do:
> 
>   - for master (and next): revert to fat for external glibc, use slim
>     for internal glibc (check for c-sky)
> 
>   - for maintenance branches: unconditionally revert to fat.
> 
> Thoughts?
> 

I'll add that tzdump probably needs to be rewritten (or fixing but a
rewrite is probably better) to handle the slim format, until then, you'd
have to use the fat format for uclibc.

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com