lib: c: io: implement standard FILE and DIR interfaces

lib/libc/io/stdio/fclose.c

@@ -0,0 +1,24 @@
+#include "file.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <mango/log.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int fclose(struct __opaque_file *stream)
+{
+	if (stream->f_fd < 0) {
+		return __set_errno(EBADF);
+	}
+
+	close(stream->f_fd);
+
+	if (stream->f_buf) {
+		free(stream->f_buf);
+	}
+
+	free(stream);
+	return SUCCESS;
+}