addrinfo incorrectly declared?

["James K. Lowden" <jklowden%schemamania.org@localhost>]

netinfo.h declares struct addrinfo in such a way that it disappears
without a preprocessor definition.  Am I missing something, or it
supposed to be that way?  

The code requires one of:

        _POSIX_C_SOURCE
        _XOPEN_SOURCE
        _NETBSD_SOURCE

Neither the standard nor the man page mention need for any of these.  

SuS:
http://pubs.opengroup.org/onlinepubs/009695399/basedefs/netdb.h.html

Code: 

/*
 * Note: ai_addrlen used to be a size_t, per RFC 2553.
 * In XNS5.2, and subsequently in POSIX-2001 and
 * draft-ietf-ipngwg-rfc2553bis-02.txt it was changed to a socklen_t.
 * To accommodate for this while preserving binary compatibility with
the
 * old interface, we prepend or append 32 bits of padding, depending on
 * the (LP64) architecture's endianness.
 *
 * This should be deleted the next time the libc major number is
 * incremented.
 */
#if (_POSIX_C_SOURCE - 0) >= 200112L || (_XOPEN_SOURCE - 0) >= 520 || \
    defined(_NETBSD_SOURCE)
struct addrinfo {
        int             ai_flags;       /*%< AI_PASSIVE,
AI_CANONNAME */ int             ai_family;      /*%< PF_xxx */
        int             ai_socktype;    /*%< SOCK_xxx */
        int             ai_protocol;    /*%< 0 or IPPROTO_xxx
for IPv4 and IPv6 */
#if defined(__sparc__) && defined(_LP64)
        int             __ai_pad0;      /* ABI compatibility */
#endif
        socklen_t        ai_addrlen;    /*%< length of ai_addr */
#if defined(__alpha__) || (defined(__i386__) && defined(_LP64))
        int             __ai_pad0;      /* ABI compatibility */
#endif
        char            *ai_canonname;  /*%< canonical name
for hostname */ struct sockaddr *ai_addr;       /*%< binary
address */ struct addrinfo      *ai_next;       /*%< next structure
in linked list */ };
#endif

--jkl