Adopted Storage support

 -Detects, decrypts, and mounts an adopted SD card if a
  secondary block device is defined (usually mmcblk1)
 -Handles unified storage
 -Displays the adopted storage in MTP along with internal
 -Factory Reset - wiped just like a data media device, we
  retain the keys folder and the storage.xml during a
  factory reset
 -Backup / Restore
 -Disable mass storage when adopted storage is present
 -Read storage nickname from storage.xml and apply it to
  display names in the GUI
 -Read storage.xml and determine what storage location is in
  use for /sdcard and remap accordingly

libgpt_twrp is source code mostly kanged from an efimanager
project. It is GPL v2 or higher, so we will opt for GPL v3.

Change-Id: Ieda0030bec5155ba8d2b9167dc0016cebbf39d55
diff --git a/gpt/gptcrc32.h b/gpt/gptcrc32.h
new file mode 100644
index 0000000..0631b7f
--- /dev/null
+++ b/gpt/gptcrc32.h
@@ -0,0 +1,36 @@
+/*
+    libparted - a library for manipulating disk partitions
+    Copyright (C) 1998-2000 Free Software Foundation, Inc.
+
+    crc32.h
+
+    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 program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+// For TWRP purposes, we'll be opting for version 3 of the GPL
+
+#ifndef _GPTCRC32_H
+#define _GPTCRC32_H
+
+#include <stdint.h>
+
+/*
+ * This computes a 32 bit CRC of the data in the buffer, and returns the CRC.
+ * The polynomial used is 0xedb88320.
+ */
+
+extern uint32_t gptcrc32 (const void *buf, unsigned long len, uint32_t seed);
+
+#endif /* _GPTCRC32_H */