lib/: Use ATTR_ACCESS() instead of /*@out@*/

The compiler seems to ignore the attribute in a function pointer,
though.

Link: <https://splint.org/manual/manual.html#undefined>
Cc: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

lib/commonio.h

@@ -11,8 +11,11 @@
 #ifndef COMMONIO_H
 #define COMMONIO_H
 
+
+#include "attr.h"
 #include "defines.h" /* bool */
 
+
 /*
  * Linked list entry.
  */
@@ -61,7 +64,8 @@ struct commonio_ops {
 	 * fgets and fputs (can be replaced by versions that
 	 * understand line continuation conventions).
 	 */
-	/*@null@*/char *(*fgets) (/*@returned@*/ /*@out@*/char *s, int n, FILE *stream);
+	ATTR_ACCESS(write_only, 1, 2)
+	/*@null@*/char *(*fgets)(/*@returned@*/char *s, int n, FILE *stream);
 	int (*fputs) (const char *, FILE *);
 
 	/*