Fix hurd build with hidden support

Fix hurd build with hidden support

	* hurd/sigunwind.c (_hurdsig_longjmp_from_handler): Destroy reply port
	of interrupted RPC instead of restoring it.

	* sysdeps/i386/setjmp.S (__sigsetjmp): Add hidden_def.
	* sysdeps/mach/hurd/accept4.c (__libc_accept4): Remove
	libc_hidden_def.
	* sysdeps/mach/hurd/dl-sysdep.c (__libc_stack_end): Add relro
	attribute, define rtld_hidden_data_def.
	* sysdeps/mach/hurd/fxstatat64.c (__fxstatat64): Add libc_hidden_def.
	* sysdeps/mach/hurd/if_index.c (__if_freenameindex): Add
	libc_hidden_def.
	(if_freenameindex): Add libc_hidden_weak.
	(if_nameindex): Add libc_hidden_weak.
	* sysdeps/mach/hurd/open.c (_open64): Rename libc_hidden_weak into
	__open64.
	* sysdeps/mach/hurd/sigwait.c (__sigwait): Add libc_hidden_def.
	* sysdeps/mach/hurd/xmknodat.c (__xmknodat): Add libc_hidden_def.
	* sysdeps/mach/nanosleep.c: Include <time.h>
	(__nanosleep): Rename to __libc_nanosleep.
	(__nanosleep): Add weak_alias.
	(nanosleep): Update alias.
	* sysdeps/mach/hurd/configure.ac (NO_HIDDEN): Do not define.
	* sysdeps/mach/hurd/configure: Regenerate.