[PATCH] C undefined behavior fix

[dewar@gnat.com]

<<This is a modification to gcc that implements pointers as triples.
While there is a performance penalty for doing this, it can completely
eliminate the problem of exploitable buffer overflows.  However, programs
that violate the rules of ISO C by generating out-of-range pointers will
fail.
>>

Note incidentally that the C rules that allow referencing the address just
past the end of an array (an irregularity that recognizes the infeasibility
of declaring the common idiom for (a=b;a<&b[10];a++)) has an interesting
consequence on a segmented machine, namely that you cannot allocate an
array too near the end of the segment.