Add SSI include file=, include virtual=

examples/file-upload/main.c

@@ -12,7 +12,8 @@ static void cb(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
     if (mg_http_match_uri(hm, "/upload")) {
       mg_http_upload(c, hm, "/tmp");
     } else {
-      mg_http_serve_dir(c, ev_data, "web_root");
+      struct mg_http_serve_opts opts = {.root_dir = "web_root"};
+      mg_http_serve_dir(c, ev_data, &opts);
     }
   }
 }