Fix sysdeps/ia64/fpu/libm-symbols.h for inclusion in testcases

[Florian Weimer]

On 11/09/2016 03:04 AM, Joseph Myers wrote:
> Tested (compilation only) for ia64.
>
> 2016-11-09  Joseph Myers  <joseph@codesourcery.com>
>
> 	* sysdeps/ia64/fpu/libm-symbols.h: Make contents conditional on
> 	[!__STRICT_ANSI__ && !__cplusplus].

Likewise, please commit this.

Thanks,
Florian