#define BITS(x) (8*sizeof(x))
#define ARRAY_LEN(x) (sizeof (x)/sizeof (x[0]))
+#define FOREACH_ARRAY_ELT(a, b) \
+ for (typeof ((b)[0]) *(a) = (b); (a) - (b) < ARRAY_LEN (b); (a)++)
#define _STRUCT_FIELD(t,f) (((t *) 0)->f)
#define STRUCT_OFFSET_OF(t,f) offsetof(t, f)