dnl Check for various features required for IPv6 support. Define a
dnl preprocessor symbol for each individual feature (HAVE_GETADDRINFO,
dnl HAVE_FREEADDRINFO, HAVE_STRUCT_ADDRINFO, HAVE_SOCKADDR_STORAGE,
dnl HAVE_SOCKADDR_IN6, HAVE_IN6_ADDR). Also set the shell variable nut_have_ipv6=yes
dnl if all the required features are present. Set nut_have_ipv6=no otherwise.

AC_DEFUN([NUT_CHECK_IPV6],
[
if test -z "${nut_check_ipv6_seen}"; then
	nut_check_ipv6_seen=yes

	AC_CHECK_FUNCS([getaddrinfo freeaddrinfo], [nut_have_ipv6=yes], [nut_have_ipv6=no])

	AC_CHECK_TYPES([struct addrinfo],
		[], [nut_have_ipv6=no], [#include <netdb.h>])

	AC_CHECK_TYPES([struct sockaddr_storage],
		[], [nut_have_ipv6=no], [#include <sys/socket.h>])

	AC_CHECK_TYPES([struct sockaddr_in6, struct in6_addr],
		[], [nut_have_ipv6=no], [#include <netinet/in.h>])

	if test "${nut_have_ipv6}" = "yes"; then
		AC_DEFINE(HAVE_IPV6, 1, [Define to enable IPv6 support])
	fi
fi
])