microtar: Update to latest upstream commit

This is a major overhaul of the library with some API
changes and ease of use improvements, particularly for
creating new archives.

The updated functionality is intended to support a new
X1000 installer framework.

Change-Id: Icf192bb546831231d49303fbf529ef1c1ce8905c

lib/microtar/src/microtar-rockbox.h

@@ -0,0 +1,29 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2021 Aidan MacDonald
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#ifndef MICROTAR_ROCKBOX_H
+#define MICROTAR_ROCKBOX_H
+
+#include "microtar.h"
+
+int mtar_open(mtar_t* tar, const char* filename, int flags);
+
+#endif