I haven't looked too deeply into the source, but it would appear that the bulk of the 64-bit problems are relegated to rts.h.
Is there any effort under way to address this? If not, I will take a whack at correcting it. If there is some experimental code out there, I'd be happy to test it on my 64 bit fedora machine.
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We can't solve problems by using the same kind of thinking we used when we created them.
- A. Einstein