Don't include private headers from user-visible part of linux/signal.h

#ifndef _LINUX_SIGNAL_H

#define _LINUX_SIGNAL_H

#include <linux/list.h>

#include <linux/spinlock.h>

#include <asm/signal.h>

#include <asm/siginfo.h>

#ifdef __KERNEL__

#include <linux/list.h>

#include <linux/spinlock.h>

/*

 * These values of sa_flags are used only by the kernel as part of the