That's just the lovely way windows handles a "segfault". Gotta be really
interesting for MS to catch all those dumps...
Anyway. Oops. Seems I ran my regression tests with the old psql, and
just managed to update the backend, when I tested that patch. Turns out
there are codepaths where we'd access the Critical Section before it was
initialized. Attached patch breaks the initializeation off to a separate
part and adds that one to a much earlier position in the program.