anchor.diff:                for right of-type array-length
                   = (min (or (position-if #'whitespacep s2 :start left) length)
                          end)
  -              thereis (and (not (= right left))
  -                           (compare-segment left right))
  +                  thereis (and (not (= right left))
  +                               (compare-segment left right))
                 until (>= right end))))))
   
   (assert (string^= "foo" "foobar"))
  
positive.code: 
  This is similar, but not identical, to SEARCH.
  
       (search nil \"foo\") => T
       (search \"nil\" \"nil\") => NIL
       (string*= nil \"foo\") => NIL
       (string*= nil \"nil\") => T"
      (call search s1 s2))
  
negative.code:   (defcmp (string~= string-tokenp) (s1 s2)
      "Does S1 occur in S2 as a token?
  
  Equivalent to
       (find S1 (tokens S2) :test #'string=),
  but without consing."
      ;; Adapted from split-sequence.
  