extern void *syscall_sp(void *t);
extern void syscall_trace(union uml_pt_regs *regs, int entryexit);
extern int hz(void);
-extern void uml_idle_timer(void);
extern unsigned int do_IRQ(int irq, union uml_pt_regs *regs);
extern int external_pid(void *t);
-extern void boot_timer_handler(int sig);
extern void interrupt_end(void);
extern void initial_thread_cb(void (*proc)(void *), void *arg);
extern int debugger_signal(int status, int pid);