I edited the code to test it since the whole affinity part was just commented out. Wolf's code changes is mostly really just that - commenting out parts here and there and writing childish comments if any. So there's no flag for affinity. I really stumbled on it by accident while studying how mr. Garzik originally implemented the miner.spfoo,
could you post your config.txt for your amd miner without cpu affinity, or do you just set the affinity section to false?
If you want to try affinity the sub-routine is still there in the beginning of the file cpu-miner.c . Then look for the call to affine_to_cpu later in the code. Just remove the comment around the call and re-compile.
Interestingly neither Jones or Wolf give any credit to the original creator of the code.