# endif
# if 0
-/* The commented out definitions below are not yet implemented in the
- GNULIB getaddrinfo() replacement, so are not yet needed and may, in fact,
- cause conflicts on systems with a getaddrinfo() function which does not
- define them.
-
- If they are restored, be sure to protect the definitions with #ifndef. */
# define AI_NUMERICHOST 0x0004 /* Don't use name resolution. */
-# define AI_V4MAPPED 0x0008 /* IPv4 mapped addresses are acceptable. */
-# define AI_ALL 0x0010 /* Return IPv4 mapped and IPv6 addresses. */
-# define AI_ADDRCONFIG 0x0020 /* Use configuration of this host to choose
- returned address type.. */
-# endif /* 0 */
+# endif
+
+/* These symbolic constants are required to be present by POSIX, but
+ our getaddrinfo replacement doesn't use them (yet). Setting them
+ to 0 on systems that doesn't have them avoids causing problems for
+ system getaddrinfo implementations that would be confused by
+ unknown values. */
+# ifndef AI_V4MAPPED
+# define AI_V4MAPPED 0 /* 0x0008: IPv4 mapped addresses are acceptable. */
+# endif
+# ifndef AI_ALL
+# define AI_ALL 0 /* 0x0010: Return IPv4 mapped and IPv6 addresses. */
+# endif
+# ifndef AI_ADDRCONFIG
+# define AI_ADDRCONFIG 0 /* 0x0020: Use configuration of this host to choose
+ returned address type. */
+# endif
/* Error values for `getaddrinfo' function. */
# ifndef EAI_BADFLAGS