* SIMPLE-VECTOR-COMPARE-AND-SWAP, not SAFE-SIMPLE-VECTOR-COMPARE-AND-SWAP.
* Missing tests.
* foreign.test.sh jugglery
This path breaks foreign.test.sh on x86/Darwin even without
touching it, indicative of still lingering Darwin issues. Any
number of changes can mask this breakage: adding SAFE- prefix to
SIMPLE-VECTOR-COMPARE-AND-SWAP is enough to make foreign.test.sh
pass again, but so is adding a sneaky --eval nil in there as well
-- among other things.
Pain. Hate. Pain. See commentary in foreign.test.sh
This time the issue doesn't seem to be foreign stack alignment
related, though: forcing the compiler to use the fast call-out path
always doesn't make the "small" case pass.