extern boolean interrupt_maybe_gc(int, siginfo_t*, void*);
extern boolean interrupt_maybe_gc_int(int, siginfo_t *, void *);
extern boolean maybe_defer_handler(void *handler, struct interrupt_data *data,
extern boolean interrupt_maybe_gc(int, siginfo_t*, void*);
extern boolean interrupt_maybe_gc_int(int, siginfo_t *, void *);
extern boolean maybe_defer_handler(void *handler, struct interrupt_data *data,