basic: introduce in_addr_data_hash_ops

src/basic/in-addr-util.h

@@ -5,6 +5,7 @@
 #include <stddef.h>
 #include <sys/socket.h>
 
+#include "hash-funcs.h"
 #include "macro.h"
 #include "util.h"
 
@@ -53,3 +54,7 @@ static inline size_t FAMILY_ADDRESS_SIZE(int family) {
 }
 
 #define IN_ADDR_NULL ((union in_addr_union) {})
+
+void in_addr_data_hash_func(const void *p, struct siphash *state);
+int in_addr_data_compare_func(const void *a, const void *b);
+extern const struct hash_ops in_addr_data_hash_ops;