anchor.diff:                      (format NIL "(asdf:load-system ~s :verbose T)" (system build))
                       "--eval"
                       (format NIL "(sb-ext:exit)"))
  -       :output T :error T))
  +       :output T :error T :on-non-zero-exit :error))
   
   (defgeneric log-contents ((build build))
     (when (probe-file (logfile build))
  
positive.code:           (finish-output log-out)
            (multiple-value-prog1
                (handler-bind ((error (lambda (err)
                                        (format log-out "~&~%~%;; !! ERROR DURING BUILD:~%")
                                        (dissect:present err log-out)
                                        (format log-out "~&~%~%")
                                        (finish-output log-out)
  
negative.code:   ())
  
  (defmethod perform-build ((build make-build))
    (run "make" ()
         :output *build-output* :error *build-output* :on-non-zero-exit :error))
  
  (defclass asdf-build (build)
    ((system :initarg :system :accessor system))
  