libtest/lib574.c: use correct callback proto

tests/libtest/lib574.c

@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -23,8 +23,10 @@
 
 #include "memdebug.h"
 
-static int new_fnmatch(const char *pattern, const char *string)
+static int new_fnmatch(void *ptr,
+                       const char *pattern, const char *string)
 {
+  (void)ptr;
   (void)pattern;
   (void)string;
   return CURL_FNMATCHFUNC_MATCH;