sbcl build host breakage

openmcl fails as build host for sbcl again.

a hash table returns a negative hash-table-count that fails
an assert in close-fasl-output (src/compiler/dump.lisp).

i tested the theory that it's just a bookkeeping bug by
removing the assert.  the build continues on but breaks
further down the line with some other code that is using a
different hash table.  (circularity detection in uncross,
src/code/uncross.lisp)

the two may be related.. it's hard to tell at the moment.

my sbcl tree is 0.9.4.52 (current of today) and this is
with openmcl 1.0-pre-050907 (DarwinPPC32)

      ...bryan