-static void *deflate_alloc __P((void *, u_int, u_int));
-static void deflate_free __P((void *, void *));
-static int deflate_common __P((struct mbuf *, struct mbuf *, size_t *, int));
-static int deflate_compress __P((struct mbuf *, struct mbuf *, size_t *));
-static int deflate_decompress __P((struct mbuf *, struct mbuf *, size_t *));
+#if ZLIB
+static void *deflate_alloc(void *, u_int, u_int);
+static void deflate_free(void *, void *);
+static int deflate_common(struct mbuf *, struct mbuf *, size_t *, int);
+static int deflate_compress(struct mbuf *, struct mbuf *, size_t *);
+static int deflate_decompress(struct mbuf *, struct mbuf *, size_t *);