[Numpy-discussion] mtrand.c update 1.11 breaks my crappy code

[Neal Becker]

I have C++ code that tries to share the mtrand state.  It unfortunately 
depends on the layout of RandomState which used to be:

struct __pyx_obj_6mtrand_RandomState {
  PyObject_HEAD
  rk_state *internal_state;
  PyObject *lock;
};

But with 1.11 it's:
struct __pyx_obj_6mtrand_RandomState {
  PyObject_HEAD
  struct __pyx_vtabstruct_6mtrand_RandomState *__pyx_vtab;
  rk_state *internal_state;
  PyObject *lock;
  PyObject *state_address;
};

So
1. Why the change?
2. How can I write portable code?