anchor.diff:            (with-controlled-compiler-conditions ()
               (funcall thunk))
           (save-forward-references forward-references)))))
  +
   (defmacro with-xcvb-compilation-unit ((&key forward-references) &body body)
     "Like WITH-COMPILATION-UNIT, but saving forward-reference issues
   for processing later (possibly in a different process)."
     `(call-with-xcvb-compilation-unit #'(lambda () ,@body) :forward-references ,forward-references))
   
   
  -;;; Interpreting commands from the xcvb-driver-command DSL.
  +;;;; ----- The xcvb-driver-command DSL for building Lisp code -----
  +
   (defun function-for-command (designator)
     (fdefinition (find-symbol* designator :xcvb-driver)))
  +
   (defun run-command (command)
     "Run a single command.
   Entry point for XCVB-DRIVER when used by XCVB's farmer"
  
positive.code:          ;;; https://bugs.launchpad.net/sbcl/+bug/310116
           (*random-state* (seed-random-state hash)))
      (funcall thunk)))
  
  (defun read-function (string)
    "Read a form from a string in function context, return a function"
    (eval `(function ,(read-from-string string))))
  
  (defun do-compile-lisp (dependencies source fasl
                          &key #+sbcl cfasl #+ecl lisp-object around-compile)
  
negative.code:   #+sbcl (sb-unix:unix-exit code)
    #-(or abcl allegro clisp clozure cmu ecl gcl lispworks mcl sbcl scl xcl)
    (error "xcvb driver: Quitting not implemented"))
  
  (defun shell-boolean (x)
    "Quit with a return code that is 0 iff argument X is true"
    (quit (if x 0 1)))
  
  (defun die (format &rest arguments)
    "Die in error with some error message"
    (format! *stderr* "~&")
    (apply #'format! *stderr* format arguments)
    (format! *stderr* "~&")
    (quit 99))
  
  (defun bork (condition)
    "Depending on whether *DEBUGGING* is set, enter debugger or die"
    (format! *stderr* "~&BORK:~%~A~%" condition)
  