sync branch rt-smart. (#6641)

* Synchronize the code of the rt mart branch to the master branch.
  * TTY device
  * Add lwP code from rt-smart
  * Add vnode in DFS, but DFS will be re-write for rt-smart
  * There are three libcpu for rt-smart:
    * arm/cortex-a, arm/aarch64
    * riscv64

Co-authored-by: Rbb666 <zhangbingru@rt-thread.com>
Co-authored-by: zhkag <zhkag@foxmail.com>

components/libc/compilers/musl/fcntl.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2021-09-02     Meco Man     First version
+ */
+
+#ifndef __FCNTL_H__
+#define __FCNTL_H__
+
+#include_next <fcntl.h>
+
+#ifndef O_DIRECTORY
+#define O_DIRECTORY 0x200000
+#endif
+
+#ifndef O_BINARY
+#define O_BINARY 0x10000
+#endif
+
+#endif