This seems to be required on Cent OS 6.5.
])
AM_CONDITIONAL(USE_SYSLOG, [test "x$syslog" = xtrue])
-AC_CHECK_HEADERS(sys/sockio.h glob.h net/if_tun.h linux/fib_rules.h)
+AC_CHECK_HEADERS(sys/sockio.h glob.h net/if_tun.h)
AC_CHECK_HEADERS(net/pfkeyv2.h netipsec/ipsec.h netinet6/ipsec.h linux/udp.h)
-AC_CHECK_HEADERS(netinet/ip6.h, [], [],
+AC_CHECK_HEADERS([netinet/ip6.h linux/fib_rules.h], [], [],
[
#include <sys/types.h>
#include <netinet/in.h>