$NetBSD: patch-ae,v 1.7 2013/07/31 06:53:21 adam Exp $

--- configure.ac.orig	2013-05-31 12:00:25.000000000 +0000
+++ configure.ac
@@ -419,6 +419,7 @@ AC_CHECK_HEADERS([ \
 	sys/mman.h sys/file.h sys/wait.h \
 	unistd.h signal.h libgen.h stropts.h \
 	syslog.h pwd.h grp.h \
+	net/if_tap.h \
 	sys/sockio.h sys/uio.h linux/sockios.h \
 	linux/types.h sys/poll.h sys/epoll.h err.h \
 ])
@@ -433,6 +434,9 @@ SOCKET_INCLUDES="
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
 #endif
+#ifdef HAVE_NET_IF_H
+#include <net/if.h>
+#endif
 #ifdef HAVE_NETINET_IN_H
 #include <netinet/in.h>
 #endif
@@ -496,6 +500,12 @@ AC_CHECK_TYPE(
 	,
 	[[${SOCKET_INCLUDES}]]
 )
+AC_CHECK_MEMBER(
+	[struct in_pktinfo.ipi_spec_dst],
+	[AC_DEFINE([HAVE_IPI_SPEC_DST], [1], [struct in_pktinfo.ipi_spec_dst needed for IP_PKTINFO support])],
+	,
+	[[${SOCKET_INCLUDES}]]
+)
 AC_CHECK_TYPE(
 	[struct sockaddr_in6],
 	,