struct sigaction *OACT;
struct sigaction *oact;
__sigaction (sig, act, oact)     int sig;     const struct sigaction *act;     struct sigaction *OACT;{  if (sig <= 0 || sig >= NSIG)    {      __set_errno (EINVAL);      return -1;    }  __set_errno (ENOSYS);  return -1;}