> The sad part if that my code does not access PyGC_Head at all. It's just a side effect when loading the code that makes it crash. :(

Python stores pointers to PyObject*. If your code doesn't access PyGC_Head directly, maybe it does acess it indirectly? I don't understand why you get a crash. It would help if you can provide more information about the crash. In which function does it happen? Try to get a gdb trace.