Update timezone code from tzcode 2017b

[Stefan Liebler]

On 06/16/2017 06:45 PM, Joseph Myers wrote:
> On Fri, 16 Jun 2017, Stan Shebs wrote:
> 
>> On Thu, Jun 15, 2017 at 5:32 PM, Joseph Myers <joseph@codesourcery.com> wrote:
>>>
>>> This patch updates files coming from tzcode to the versions in tzcode
>>> 2017b.
>>
>> So this blows up for me compiling with GCC 4.8.4 (yes yes I know, it's
>> what Google makes me use), which doesn't like the _Generic in
>> timezone/private.h.
>>
>> Does it make sense to try to borrow the __HAVE_GENERIC_SELECTION added
>> for float128, or is this more of a sign to start requiring 4.9 as the
>> minimum?
> 
> We don't want to have local changes to the files from tzcode.  Presumably
> this is from the -std=gnu11, which sets __STDC_VERSION__ but was
> incomplete in GCC 4.8.  I think requiring GCC >= 4.9 and binutils >= 2.25
> (the latter given internal linker errors on x86 with 2.24) is reasonable
> for building glibc.
> 

As information:
I've also run into the same issue with _Generic on s390 with GCC 4.8.5.
Do you propose a patch which adds such a configure check?

Bye
Stefan