Fix sysdeps/unix/sysv/linux/arm/libc-do-syscall.S warning

[Carlos O'Donell]

On 03/02/2015 06:13 PM, Joseph Myers wrote:
> On Sun, 1 Mar 2015, Mike Frysinger wrote:
> 
>> On 26 Nov 2014 15:14, Joseph Myers wrote:
>>> This patch fixes a warning
>>>
>>> ../include/features.h:328:4: warning: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Wcpp]
>>>
>>> seen when building for ARM.  This warning comes from libc-do-syscall.S
>>> being built for nscd: the nscd build uses _FORTIFY_SOURCE, while .S
>>> files aren't built with -O, and the combination produces a warning.
>>> As _FORTIFY_SOURCE doesn't do anything for .S files, undefining it in
>>> libc-do-syscall.S seems the simplest solution.
>>
>> should we update features.h to avoid that define when __ASSEMBLER__ is defined ?
>> seems like this warning can impact external code too.
> 
> I don't know.  To what extent do we support users including glibc header 
> files from assembler code?

To the extent that it builds glibc without warnings?

Cheers,
Carlos.