+
+#if !defined(RTS_SUPPORTS_THREADS)
+
+extern StgPtr pending_handler_buf[];
+extern StgPtr *next_pending_handler;
+#define signals_pending() (next_pending_handler != pending_handler_buf)
+extern void awaitUserSignals(void);
+
+#else
+
+extern void startSignalHandler(int sig);
+
+#endif