Update MentOs code to the latest development version.

libc/inc/stdbool.h

@@ -0,0 +1,13 @@
+///                MentOS, The Mentoring Operating system project
+/// @file stdbool.h
+/// @brief Defines the boolean values.
+/// @copyright (c) 2014-2021 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#pragma once
+
+/// @brief Define boolean value.
+typedef enum bool_t {
+    false, ///< [0] False.
+    true ///< [1] True.
+} __attribute__((__packed__)) bool_t;