#define UNIQ_T(x, uniq) CONCATENATE(__unique_prefix_, CONCATENATE(x, uniq))
#define UNIQ __COUNTER__
+/* builtins */
+#if __SIZEOF_INT__ == 4
+#define BUILTIN_FFS_U32(x) __builtin_ffs(x);
+#elif __SIZEOF_LONG__ == 4
+#define BUILTIN_FFS_U32(x) __builtin_ffsl(x);
+#else
+#error "neither int nor long are four bytes long?!?"
+#endif
+
/* Rounds up */
#define ALIGN4(l) (((l) + 3) & ~3)