Fix segfault when a non-matching filter is applied twice

noice.c

@@ -678,7 +678,8 @@ nochange:
 			filter_re = re;
 			DPRINTF_S(filter);
 			/* Save current */
-			oldpath = makepath(path, dents[cur].name);
+			if (n > 0)
+				oldpath = makepath(path, dents[cur].name);
 			goto out;
 		case SEL_NEXT:
 			if (cur < n - 1)