[jhc] foreign ptr bugs

[John Meacham]

I have narrowed it down to the -fstrict-aliasing optimization pass
that is causing the bug. So it is likely that I am accidentally
aliasing some memory location via two different pointer types. hmm...
not sure how to proceed debugging this other than manual inspection of
the generated assembly. Has anyone out there dealt with aliasing
issues before? I'd prefer to figure out the root cause than just
disable the optimization without understanding why it is needed.

    John