Make initializer braces non-empty in json_parse for ISO C compliance

json.c

@@ -787,7 +787,7 @@ json_value * json_parse_ex (json_settings * settings,
 
 json_value * json_parse (const json_char * json, size_t length)
 {
-   json_settings settings = {};
+   json_settings settings = { 0 };
    return json_parse_ex (&settings, json, length, 0);
 }