anchor.diff:                          (setf largest-free-space (max largest-free-space size)))
                          ((#.+object-tag-instance+
                            #.+object-tag-funcallable-instance+)
  -                        (add-class (layout-class (%instance-layout object)))))))))
  +                        (add-class (layout-class (%instance-layout object))))
  +                       (#.+object-tag-obsolete-instance+
  +                        (add-class (class-of object))))))))
       (values allocated-words total-words largest-free-space
               n-allocated-objects allocated-objects-sizes allocated-classes)))
   
  
positive.code:     cons                       ; #b111000
      freelist-entry             ; #b111001
      weak-pointer               ; #b111010
      'mezzano.delimited-continuations:delimited-continuation ; #b111011
      function                   ; #b111100
      funcallable-instance       ; #b111101
      closure                    ; #b111110
  
negative.code:     mezzano.simd:mmx-vector    ; #b101111
      symbol                     ; #b110000
      instance                   ; #b110001
      obsolete-instance          ; #b110010
      mezzano.simd:sse-vector    ; #b110011
      thread                     ; #b110100
      unbound-value              ; #b110101
  