CHECK_1opt (act), CHECK_1opt (oact), _NSIG / 8);
CHECK_1_NULL_OK (act), CHECK_1_NULL_OK (oact), _NSIG / 8);
__libc_sigaction (sig, act, oact)     int sig;     const struct sigaction *act;     struct sigaction *oact;{  /* XXX The size argument hopefully will have to be changed to the     real size of the user-level sigset_t.  */  return INLINE_SYSCALL (rt_sigaction, 4, sig,			 CHECK_1opt (act), CHECK_1opt (oact), _NSIG / 8);}