Fix sparc64 bits/setjmp.h namespace (bug 21261)

[Joseph Myers]

On Fri, 17 Mar 2017, David Miller wrote:

> From: Joseph Myers <joseph@codesourcery.com>
> Date: Fri, 17 Mar 2017 03:08:58 +0000
> 
> > sysdeps/unix/sysv/linux/sparc/bits/setjmp.h defines 64-bit __jmp_buf
> > with a load of identifiers that are not part of any standard
> > namespace, resulting in conform/ tests failing.  This patch fixes this
> > by moving those identifiers to the implementation namespace, so
> > enabling the conform/ tests to pass for sparc64.
> 
> This is going to break the build of the address sanitizer on sparc64.
> 
> It will also probably break lots of other programs too that grovel
> through the mcontext register bits for unwinding and state inspection.

Are those things really looking at jmp_buf, rather than ucontext / 
mcontext from sys/ucontext.h (which are unchanged by the patch)?

-- 
Joseph S. Myers
joseph@codesourcery.com