fix unused parameter warning on windows

libs/stfu/stfu.c

@@ -821,6 +821,9 @@ STFU_DECLARE(int32_t) stfu_n_copy_next_frame(stfu_instance_t *jb, uint32_t times
 
 	uint32_t target_ts = 0;
 
+#ifdef WIN32
+	seq = seq;
+#endif
 	if (!next_frame) return 0;
 
 	target_ts = timestamp + (distance - 1) * jb->samples_per_packet;