extern void interrupt_handle_pending(os_context_t*);
extern void interrupt_internal_error(int, siginfo_t*, os_context_t*,
boolean continuable);
+extern boolean handle_control_stack_guard_triggered(os_context_t *,void *);
extern boolean interrupt_maybe_gc(int, siginfo_t*, void*);
extern void undoably_install_low_level_interrupt_handler (int signal,
void