anchor.diff:  (defcfun "pair_plus_one_sum" :int
     (p (:struct pair+1)))
   
  +#+#:unused
   (defcfun "pair_plus_one_pointer_sum" :int
     (p (:pointer (:struct struct-pair+1))))
   
  
positive.code:     (alloc-pair-plus-one 1 2 3)
    ((1 . 2) . 3))
  
  #+#:unimplemented
  (defcfun "pair_sum" :int
    (p (:struct pair)))
  
  #+#:unimplemented
  (defcfun "make_pair" (:struct pair)
    (a :int)
    (b :int))
  
  #|| ; TODO: load cffi-libffi for these tests to work.
  (deftest struct-values.fn.1
      (with-foreign-object (p '(:struct pair))
        (with-foreign-slots ((a b) p (:struct pair))
          (setf a -1 b 2)
          (pair-sum p)))
    1)
  
  (deftest struct-values.fn.2
      (pair-sum '(3 . 5))
    8)
  
  (deftest struct-values.fn.3
      (with-foreign-object (p '(:struct pair))
        (make-pair 7 11 :result-pointer p)
        (with-foreign-slots ((a b) p (:struct pair))
          (cons a b)))
    (7 . 11))
  
  (deftest struct-values.fn.4
      (make-pair 13 17)
    (13 . 17))
  ||#
  
  (defcstruct single-byte-struct
    (a :uint8))
  
negative.code:   1
    2)
  
  (defcstruct (struct-pair+double)
    (pr (:struct struct-pair-default-translate))
    (dbl :double))
  
  