db/proxy: copy "Last-Modified" from remote directories

NEWS

@@ -4,6 +4,7 @@ ver 0.19 (not yet released)
   - "lsinfo" and "readcomments" allowed for remote files
 * database
   - proxy: forward "idle" events
+  - proxy: copy "Last-Modified" from remote directories
   - upnp: new plugin
 * playlist
   - soundcloud: use https instead of http

src/db/ProxyDatabasePlugin.cxx

@@ -525,9 +525,10 @@ Visit(struct mpd_connection *connection,
       VisitPlaylist visit_playlist, Error &error)
 {
 	const char *path = mpd_directory_get_path(directory);
+	time_t mtime = mpd_directory_get_last_modified(directory);
 
 	if (visit_directory &&
-	    !visit_directory(LightDirectory(path, 0), error))
+	    !visit_directory(LightDirectory(path, mtime), error))
 		return false;
 
 	if (recursive &&