[libc] implement extension standard C functions (#6044)

* implement extension standard C functions

components/libc/compilers/common/include/posix/stdio.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2006-2022, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2022-06-07     Meco Man     first version
+ */
+
+#ifndef __POSIX_STDIO_H__
+#define __POSIX_STDIO_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdio.h>
+#include <sys/types.h>
+
+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__ */