apparently recent gcc versions have intentionally broken the
traditional definition by treating it as a non-constant expression.
the traditional definition may also be problematic for c++ programs.
#include <bits/alltypes.h>
#include <bits/alltypes.h>
+#if __GNUC__ > 3
+#define offsetof(type, member) __builtin_offsetof(type, member)
+#else
#define offsetof(type, member) ((size_t)( (char *)&(((type *)0)->member) - (char *)0 ))
#define offsetof(type, member) ((size_t)( (char *)&(((type *)0)->member) - (char *)0 ))