[disable IPv6, for IPv4 only network stacks])],
[if test "x$enableval" = xno; then
AC_DEFINE([USE_IPV4_ONLY], 1, [Define to not use IPv6.])
fi])
[disable IPv6, for IPv4 only network stacks])],
[if test "x$enableval" = xno; then
AC_DEFINE([USE_IPV4_ONLY], 1, [Define to not use IPv6.])
fi])