#endif
#ifdef FIO_INTERNAL
-#define ARRAY_SIZE(x) (sizeof((x)) / (sizeof((x)[0])))
-#define FIELD_SIZE(s, f) (sizeof(((__typeof__(s))0)->f))
+#define FIO_ARRAY_SIZE(x) (sizeof((x)) / (sizeof((x)[0])))
+#define FIO_FIELD_SIZE(s, f) (sizeof(((__typeof__(s))0)->f))
+#endif
+
+#ifndef __has_attribute
+#define __GCC4_has_attribute___fallthrough__ 0
+#endif
+
+#if __has_attribute(__fallthrough__)
+#define fallthrough __attribute__((__fallthrough__))
+#else
+#define fallthrough do {} while (0) /* fallthrough */
#endif
#endif