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

lib/libc/io/stdio/closedir.c

@@ -0,0 +1,19 @@
+#include "dir.h"
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int closedir(struct __opaque_dir *dirp)
+{
+	close(dirp->d_fd);
+
+	if (dirp->d_buf) {
+		free(dirp->d_buf);
+	}
+
+	free(dirp);
+	return SUCCESS;
+}