* hurd/hurdsig.c (_hurd_internal_post_signal): Support SA_RESETHAND

* hurd/hurdsig.c (_hurd_internal_post_signal): Support SA_RESETHAND

	and SA_NODEFER options.  Spurred to action by Igor Khavkine.

	* sysdeps/generic/bits/sigaction.h [__USE_UNIX98 || __USE_MISC]
	(SA_NODEFER, SA_RESETHAND): New macros, same bit values as FreeBSD.
	[__USE_MISC] (SA_INTERRUPT): New macro, value 0.
	[__USE_MISC] (SA_NOMASK, SA_ONESHOT, SA_STACK): New macros, aliases
	as in other sysdeps versions of this file.

        * sysdeps/generic/bits/sigaction.h (struct sigaction): Use a union
	and provide sa_handler and sa_sigaction member names as macros, as
	done in other sysdeps versions of this file.
	Suggested by Igor Khavkine <i_khavki@alcor.concordia.ca>.