-#define FLAG_GROUP 1 /* ' flag */
-#define FLAG_LEFT 2 /* - flag */
-#define FLAG_SHOWSIGN 4 /* + flag */
-#define FLAG_SPACE 8 /* space flag */
-#define FLAG_ALT 16 /* # flag */
-#define FLAG_ZERO 32
+#define FLAG_GROUP 1 /* ' flag */
+#define FLAG_LEFT 2 /* - flag */
+#define FLAG_SHOWSIGN 4 /* + flag */
+#define FLAG_SPACE 8 /* space flag */
+#define FLAG_ALT 16 /* # flag */
+#define FLAG_ZERO 32
+#if __GLIBC__ >= 2 && !defined __UCLIBC__
+# define FLAG_LOCALIZED 64 /* I flag, uses localized digits */
+#endif