fix build errors with -DNDEBUG

[Carlos O'Donell]

On 07/20/2015 03:20 AM, Mike Frysinger wrote:
> On 17 Jul 2015 11:36, Andreas Schwab wrote:
>> Mike Frysinger <vapier@gentoo.org> writes:
>>> we have __attribute_used__ ...
>>
>> That's actually obsolete now that we require gcc >= 4.6.
> 
> right, for internal source files.  __attribute_used__ is kept around though for
> public headers since we don't require newer gcc versions to build against glibc.
> which leads to me forgetting and always using the defines both in internal and
> in public code (better than forgetting and never using the defines even in the
> public headers?).
> -mike

Yes it is better :-)

We should make our internal headers cause a warning to be emitted if you use
obsolete attributes given the newly required gcc to build glibc, but we haven't
gotten around to it.

c.