anchor.diff:  (defun transpiler-add-used-function (tr x)
     (= (href (transpiler-used-functions tr) x) t)
     x)
  +
  +(defun transpiler-configuration-item (tr x)
  +  (alet (transpiler-configurations tr)
  +    (| (assoc x ! :test #'eq)
  +       (error "Transpiler ~A has no configuration item ~A. Available items are ~A."
  +              (transpiler-name tr) x (carlist !)))))
  +
  +(defun transpiler-configuration (tr x)
  +  (cdr (transpiler-configuration-item tr x)))
  +
  +(defun (= transpiler-configuration) (value tr x)
  +  (= (cdr (transpiler-configuration-item tr x)) value))
  
positive.code:   (predefined-symbols       nil)
  
    (postprocessor            #'concat-stringtree)
  
    ;;;
    ;;; You mustn't init these.
  
negative.code:         :cps-wrappers             (copy-hash-table cps-wrappers)
          :native-cps-functions     (copy-hash-table native-cps-functions)
          :postprocessor            postprocessor
          :configurations           (copy-alist configurations)
          :make-text?               make-text?
          :encapsulate-strings?     encapsulate-strings?
          :dump-passes?             dump-passes?
  