Include local lwtunnel.h unless found in system

AC_CHECK_HEADER(syslog.h, [AC_DEFINE(HAVE_SYSLOG)])

AC_CHECK_HEADER(alloca.h, [AC_DEFINE(HAVE_ALLOCA_H)])

AC_CHECK_HEADER([linux/lwtunnel.h], [AC_DEFINE(HAVE_LWTUNNEL)])

AC_MSG_CHECKING(whether 'struct sockaddr' has sa_len)

AC_TRY_COMPILE([#include <sys/types.h>

  #include <sys/socket.h>

/* We have LibSSH */

#undef HAVE_LIBSSH

/* We have linux lwtunnel */

#undef HAVE_LWTUNNEL

#define CONFIG_PATH ?

#ifndef _LWTUNNEL_H_

#define _LWTUNNEL_H_

#include <linux/types.h>

enum lwtunnel_encap_types {

	LWTUNNEL_ENCAP_NONE,

	LWTUNNEL_ENCAP_MPLS,

	LWTUNNEL_ENCAP_IP,

	LWTUNNEL_ENCAP_ILA,

	LWTUNNEL_ENCAP_IP6,

	__LWTUNNEL_ENCAP_MAX,

};

#define LWTUNNEL_ENCAP_MAX (__LWTUNNEL_ENCAP_MAX - 1)

enum lwtunnel_ip_t {

	LWTUNNEL_IP_UNSPEC,

	LWTUNNEL_IP_ID,

	LWTUNNEL_IP_DST,

	LWTUNNEL_IP_SRC,

	LWTUNNEL_IP_TTL,

	LWTUNNEL_IP_TOS,

	LWTUNNEL_IP_FLAGS,

	LWTUNNEL_IP_PAD,

	__LWTUNNEL_IP_MAX,

};

#define LWTUNNEL_IP_MAX (__LWTUNNEL_IP_MAX - 1)

enum lwtunnel_ip6_t {

	LWTUNNEL_IP6_UNSPEC,

	LWTUNNEL_IP6_ID,

	LWTUNNEL_IP6_DST,

	LWTUNNEL_IP6_SRC,

	LWTUNNEL_IP6_HOPLIMIT,

	LWTUNNEL_IP6_TC,

	LWTUNNEL_IP6_FLAGS,

	LWTUNNEL_IP6_PAD,

	__LWTUNNEL_IP6_MAX,

};

#define LWTUNNEL_IP6_MAX (__LWTUNNEL_IP6_MAX - 1)

#endif /* _LWTUNNEL_H_ */

#include <asm/types.h>

#include <linux/if.h>

#ifdef HAVE_LWTUNNEL

#include <linux/lwtunnel.h>

#else

#include "sysdep/linux/lwtunnel.h"

#endif

#include <linux/netlink.h>

#include <linux/rtnetlink.h>