Mixing BC and CNI in the same executable

[Stephen Kell]

> Thanks.
> 
> I've seen something like this years ago, but I can't remember what
> caused it.  I expect it's something quite simple, but I can't tell
> from what you've posted here.
> 
> If you can make a self-contained test case theat reproduces the
> problem I'll debug it.

Great -- thanks! The following tarball *should* be self-contained...
"make testcase" should trigger the bug.

http://www.cl.cam.ac.uk/~srk31/private/testcase-20100125.tar.bz2

Stephen