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

[Roland McGrath]

> 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?

We only need macros in sys/cdefs.h for things we're going to use in public
header files.  If something is only used in libc sources but a macro is
useful, it goes in libc-symbols.h instead.  But we only need a macro if
either the plain syntax is very hairy to write so a shorthand is especially
worthwhile, or if the details need to vary based on compiler version or
other such conditionals.  I don't think any of these apply here.


Thanks,
Roland