fix compilation when HAVE_ZLIB is not defined
diff --git a/libtelnet.c b/libtelnet.c
index e905287..4d3d067 100644
--- a/libtelnet.c
+++ b/libtelnet.c
@@ -84,6 +84,7 @@
 	return err;
 }
 
+#ifdef HAVE_ZLIB
 /* initialize the zlib box for a telnet box; if deflate is non-zero, it
  * initializes zlib for delating (compression), otherwise for inflating
  * (decompression).  returns LIBTELNET_EOK on success, something else on
@@ -124,6 +125,7 @@
 
 	return LIBTELNET_EOK;
 }
+#endif
 
 /* push bytes out, compressing them first if need be */
 static void _send(libtelnet_t *telnet, const unsigned char *buffer,
@@ -391,6 +393,7 @@
 		telnet->buffer_pos = 0;
 	}
 
+#ifdef HAVE_ZLIB
 	/* free zlib box */
 	if (telnet->z != 0) {
 		if (telnet->flags & LIBTELNET_PFLAG_DEFLATE)
@@ -400,6 +403,7 @@
 		free(telnet->z);
 		telnet->z = 0;
 	}
+#endif
 
 	/* free RFC1143 queue */
 	if (telnet->q) {