+#ifdef LISP_FEATURE_SB_THREAD
+ undoably_install_low_level_interrupt_handler(SIG_INTERRUPT_THREAD,
+ interrupt_thread_handler);
+ undoably_install_low_level_interrupt_handler(SIG_STOP_FOR_GC,
+ sig_stop_for_gc_handler);
+ undoably_install_low_level_interrupt_handler(SIG_THREAD_EXIT,
+ thread_exit_handler);
+#endif
+}
+
+#ifdef LISP_FEATURE_SB_THREAD
+int
+futex_wait(int *lock_word, int oldval)
+{
+ int t= sys_futex(lock_word,FUTEX_WAIT,oldval, 0);
+ return t;