AC_ARG_ENABLE(ipv6,
[  --enable-ipv6           Enable IPv6 support],
        if test x$enableval = xyes; then
                want_ipv6=yes
        else
                if test "x$enableval" = xno; then
                        want_ipv6=no
                else
                        want_ipv6=yes
                fi
        fi,
        want_ipv6=no)


icpld_cv_type_in6_addr=no
if test "x$want_ipv6" = "xyes"; then
        AC_MSG_CHECKING([for IPv6])
        AC_TRY_COMPILE([
                 #include <sys/types.h>
                 #include <sys/socket.h>
                 #include <netinet/in.h>
                 #include <netdb.h>
                 #include <arpa/inet.h>],
                [struct in6_addr i;],
                [icpld_cv_type_in6_addr=yes])
        AC_MSG_RESULT([$icpld_cv_type_in6_addr])
        if test "$icpld_cv_type_in6_addr" = "yes"; then
                AC_DEFINE([HAVE_IPV6], [1], [Whether to include IPv6 support])
                # User can override with ./configure PING6="/foo/bar -6"
                AC_ARG_VAR([PING6],[IPv6 ping6 or equivalent command])
                if test "x$PING6" = "x"; then
                        AC_CHECK_PROG([PING6],[ping6],[ping6],[ping -A inet6])
                fi
                AC_DEFINE_UNQUOTED([PING6], ["${PING6}"], [How to call an IPv6 ping using the shell])
        else
                PING6=false # !HAVE_IPV6, so let PING6 fail
        fi
        AC_SUBST([PING6])
fi
AM_CONDITIONAL([HAVE_IPV6], [test "$icpld_cv_type_in6_addr" = "yes"])