Work around IA64 tst-setcontext2.c compile failure

[Florian Weimer]

On 11/09/2016 03:05 AM, Joseph Myers wrote:
> Tested (compilation only) for ia64.
>
> 2016-11-09  Joseph Myers  <joseph@codesourcery.com>
>
> 	* sysdeps/unix/sysv/linux/ia64/tst-setcontext2.c: New file.

Please feel encouraged to commit this.

Honestly, I don't really know what to do with these old architectures.

Thanks,
Florian