Merge support for very early alchemy port. I wouldn't merge this
except I don't want it to get lost when we retire projects/mips.
Should be consiered pre-alpha at this stage. Also, alchemy is now
owned by rmi, but started out life as a separate processor line, so
I'm leaving it in its own directory rather than try to shoe-horn it
into the unrelated rmi directory. Its future location is an open
question.
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