+# if PTHREAD_SIGMASK_FAILS_WITH_ERRNO
+ if (ret == -1)
+ return errno;
+# endif
+# if PTHREAD_SIGMASK_UNBLOCK_BUG
+ if (ret == 0
+ && new_mask != NULL
+ && (how == SIG_UNBLOCK || how == SIG_SETMASK))
+ {
+ /* Give the OS the opportunity to raise signals that were pending before
+ the pthread_sigmask call and have now been unblocked. */
+ usleep (1);
+ }
+# endif