anchor.diff:                                                   source
                                                    standard
                                                    options
  -                                                 arguments
                                                    shared)
       (invoke c-compiler
               (shellify
  
positive.code:                                                   source
                                                    standard
                                                    options
                                                    arguments
                            &allow-other-keys)
    (:method ((compiler T) from to &rest args &key)
      (apply #'c-preprocess *default-compiler* from to args))
    (:method ((c-compiler c-compiler) from to &key warnings
                                                   source
                                                   standard
                                                   options
                                                   arguments)
      (invoke c-compiler
              (shellify
               ("-E~*" T)
  
negative.code:                                                 source
                                                  standard
                                                  options
                          &allow-other-keys)
    (:method ((compiler T) from to &rest args &key)
      (apply #'c-assemble *default-compiler* from to args))
  