+# if defined(SIG_BLOCK)
+ /* Use POSIX/SYSV interface */
+# define SIGSET_T sigset_t
+# define SIG_DEL(set, signal) sigdelset(&(set), (signal))
+# define SIG_FILL(set) sigfillset(&set)
+# define SIGSETMASK(old, new) sigprocmask(SIG_SETMASK, &(new), &(old))
+# elif defined(sigmask) && !defined(UTS4) && !defined(HURD)