-AC_CHECK_FUNCS([access atexit getaddrinfo getcwd gethostbyaddr gethostbyaddr_r gethostbyname gethostbyname_r getnameinfo gettimeofday inet_ntoa localtime_r memchr memmove memset poll putenv random regcomp select setlocale snprintf socket strchr strdup strerror strftime strlcat strlcpy strptime strstr strtoul timegm tzset])
-
+AC_CHECK_FUNCS([access atexit getcwd gethostbyaddr gethostbyaddr_r gethostbyname gethostbyname_r gettimeofday inet_ntoa localtime_r memchr memmove memset poll putenv random regcomp select setlocale snprintf socket strchr strdup strerror strftime strlcat strlcpy strptime strstr strtoul timegm tzset])
+
+dnl Checks for RFC 2553 resolver and socket functions
+AC_CHECK_FUNC([getaddrinfo],
+ [AC_CHECK_FUNC([getnameinfo],
+ [AC_DEFINE([HAVE_RFC2553], [1],
+ [Define if RFC 2553 resolver functions like getaddrinfo(3) and
+ getnameinfo(3) present])
+ ])
+])