[PATCH] C undefined behavior fix

[dewar@gnat.com]

<<However, I think we have to turn off looking through the + in
        (typeof pointer)((unsigned long)(pointer) + expression)

to be correct, or, rather, remove any assumption that we know where
the resulting pointer points.  We cannot assume that the above
expression is equivalent to
>>

OK, that's the start of a semantic proposal, but it will not be easy
to formalize what you mean by "looking through" here.