添加rtthread相关代码

riscv/rtthread/components/libc/posix/io/stdio/posix/stdio.h

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2006-2021, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2017/10/15     bernard      the first version
+ */
+
+#ifndef __POSIX_STDIO_H__
+#define __POSIX_STDIO_H__
+
+#include <rtconfig.h>
+#include <stdio.h>
+#include <sys/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int rt_posix_stdio_init(void);
+int rt_posix_stdio_get_console(void);
+int rt_posix_stdio_set_console(const char* device_name, int mode);
+ssize_t getdelim(char **lineptr, size_t *n, int delim, FILE *stream);
+ssize_t getline(char **lineptr, size_t *n, FILE *stream);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __POSIX_STDIO_H__ */