+ /* --- Sort out the signal handling for the parent --- *
+ *
+ * Block @SIGCHLD@ while this is going on. Unlike the standard @system@
+ * function, I won't disable @SIGINT@ and @SIGQUIT@. Then, if the user
+ * stops the child with a terminal signal, the parent (i.e., me) gets
+ * killed too, and I don't end up with a tiny dribble of entropy when I'm
+ * expecting quite a lot.
+ */
+
+#ifdef HAVE_SIGPROCMASK
+ sigemptyset(&nb);
+ sigaddset(&nb, SIGCHLD);
+ if (sigprocmask(SIG_BLOCK, &nb, &ob))
+ goto fail_0;
+#endif
+