[COMMITTED PATCH] suppress new -Wunused-but-set warnings in GMP code

[Marek Polacek]

On Thu, Aug 16, 2012 at 02:11:21PM -0700, Roland McGrath wrote:
> +	      mp_limb_t __attribute__ ((unused));

Do we want to define __attribute_unused__ in cdefs.h?

	Marek