x1000-installer: Initial commit of new framework

This is a new flash installer framework for the X1000 targets.

A bunch of this code is *UNTESTED* but there is an external test
harness which allows the library to be built and tested on a PC.

Once tests are written and the bugs are ironed out this framework
will replace the existing installer code.

New features:

- Update tarballs are MD5-checksummed to guarantee integrity.
- The flash map is no longer fixed -- updates are self describing and
  carry a map file which specifies the areas to update.
- Can take full or partial backups with checksums computed on the fly.
- Supports an additional verification mode which reads back data after
  writing to ensure the flash contents were not silently corrupted.

Change-Id: I29a89190c7ff566019f6a844ad0571f01fb7192f

lib/x1000-installer/include/xf_error.h

@@ -0,0 +1,43 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   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 _XF_ERROR_H_
+#define _XF_ERROR_H_
+
+enum {
+    XF_E_SUCCESS            = 0,
+    XF_E_IO                 = -1,
+    XF_E_LINE_TOO_LONG      = -2,
+    XF_E_FILENAME_TOO_LONG  = -3,
+    XF_E_INT_OVERFLOW       = -4,
+    XF_E_BUF_OVERFLOW       = -5,
+    XF_E_SYNTAX_ERROR       = -6,
+    XF_E_INVALID_PARAMETER  = -7,
+    XF_E_NAND               = -8,
+    XF_E_OUT_OF_MEMORY      = -9,
+    XF_E_OUT_OF_RANGE       = -10,
+    XF_E_VERIFY_FAILED      = -11,
+    XF_E_CANNOT_OPEN_FILE   = -12,
+};
+
+const char* xf_strerror(int err);
+
+#endif /* _XF_ERROR_H_ */