Self-compile and mlton.cm

[Matthew Fluet]

I'm having problems doing a self-compile with the 20001004 version I
downloaded yesterday.  I'm getting an "x_221 has no operand property"
error being raised in the backend/allocate-registers phase.  The only
modifications I made to anything outside the x86-codegen directory were
fairly minor.  The nj-mlton version builds fine, and that passes all of
the regression tests and benchmarks.  It's just when I turn that on
mlton.sml that it fails.  One other difference is that I'm constructing a
mlton.sml in the following way:
mlton -stop f mlton.cm | xargs cat > mlton.sml
(just because some of my scripts were relying on a .sml file).  If there
were parsing and typechecking errors, I would have thought my sources.cm
file was wrong, but there aren't.  Any ideas?