Add empty template for BITLK device type.

Also add DM_ZERO type for multi-segment mapping.

lib/bitlk/bitlk.h

@@ -0,0 +1,43 @@
+/*
+ * BITLK (BitLocker-compatible) header definition
+ *
+ * Copyright (C) 2019 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2019 Milan Broz
+ *
+ * This file is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this file; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef _CRYPTSETUP_BITLK_H
+#define _CRYPTSETUP_BITLK_H
+
+#include <stdint.h>
+#include <stddef.h>
+
+struct crypt_device;
+struct device;
+struct crypt_params_bitlk;
+
+int BITLK_read_sb(struct crypt_device *cd, struct crypt_params_bitlk *params);
+
+int BITLK_dump(struct crypt_device *cd, struct device *device);
+
+int BITLK_activate(struct crypt_device *cd,
+		   const char *name,
+		   const char *password,
+		   size_t passwordLen,
+		   const struct crypt_params_bitlk *params,
+		   uint32_t flags);
+
+#endif