- added a missing save to a callee-save register (%edi)
when entering/reentering to Scheme which caused Ikarus
not to run properly depending on whether or not gcc places
the pcb in %edi or not during Scheme execution.
- updated lab/test-ffi.ss to use the new names for foreign
types, etc.
continuations work, more assembly instructions are testing in 64-bit
mode, and some arithmetic operations (shift-right, etc.) have been
fixed by removing some 32-bit dependencies.