[tz] zic changes (2/2)

[Paul Eggert]

On Wed, 2 Mar 2016 23:41:22 +0100 Aurelien Jarno wrote:

> It happens that this patch causes the generated zoneinfo files to not
> behave correctly wrt daylight saving time on 32-bit machines. On 64-bit
> machines or before this patch one get:
>
>    $ TZ=PST+8PDT date --date=@1152995400
>    Sat Jul 15 13:30:00 PDT 2006
>
> With this patch on 32-bit machines, one get:
>
>    $ TZ=PST+8PDT date --date=@1152995400
>    Sat Jul 15 12:30:00 PST 2006
>
> As you can see the daylight saving time is not applied.

I reproduced this problem on Fedora 23 x86 with glibc 2.22-11.fc23, by building 
tzcode as follows:

$ make clean
$ make CFLAGS='-m32' DATEOBJS=date.o date
$ TZ=PST+8PDT ./date -r 1152995400 +'%Y-%m-%d %H:%M:%S %z %Z'
2006-07-15 12:30:00 -0800 PST

However, if I use GNU glibc built from git (sourceware.org commit 
4e940b2f4b577f3a530e0580373f7c2d569f4d63, configured with '../glibc/configure 
CC=gcc -m32 --build=i486-pc-linux-gnu --prefix=/tmp/prefix') the problem goes away:

$ make clean
$ make CFLAGS='-m32 -Wl,--rpath=/tmp/prefix/lib 
-Wl,--dynamic-linker=/tmp/prefix/lib/ld-linux.so.2' DATEOBJS=date.o date
$ TZ=PST+8PDT ./date -r 1152995400 +'%Y-%m-%d %H:%M:%S %z %Z'
2006-07-15 13:30:00 -0700 PDT

> This is reproducible with
> GNU libc from git as the date of today.

Which glibc commit were you using? Does it contain any patches compared to 
upstream glibc?

I assume your commit contain the fix for glibc bug 19253. This was fixed in 
commit c83196b0df4340209f260ffaf90e787c711c268e in November. This issue seems to 
be on point. See:

https://sourceware.org/bugzilla/show_bug.cgi?id=19253

Does the problem go away if you revert commit 
c83196b0df4340209f260ffaf90e787c711c268e?