+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE) || defined(_POSIX_SOURCE) \
+ || (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE+0 < 200809L) \
+ || (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE+0 < 700)
+struct hostent *gethostbyname (const char *);
+struct hostent *gethostbyaddr (const void *, socklen_t, int);
+#ifdef __GNUC__
+__attribute__((const))
+#endif
+int *__h_errno_location(void);
+#define h_errno (*__h_errno_location())
+#define HOST_NOT_FOUND 1
+#define TRY_AGAIN 2
+#define NO_RECOVERY 3
+#define NO_DATA 4
+#define NO_ADDRESS NO_DATA
+#endif
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+void herror(const char *);