anchor.diff:               (run-program command :pipe nil)
                #+ecl (ext:system command)
                #+cormanlisp (win32:system command)
  +             #+mcl (ccl::with-cstrs ((%command command)) (_system %command))
                #+gcl (lisp:system command)
                #+(and lispworks os-windows)
                (system:call-system-showing-output
  
positive.code: 
  (defun getcwd ()
    "Get the current working directory as per POSIX getcwd(3)"
    (or #+ccl (ccl:current-directory)
        #+clisp (ext:default-directory)
        #+sbcl (sb-posix:getcwd)
        (error "getcwd not supported on your implementation")))
  
  (defun chdir (x)
    "Change current directory, as per POSIX chdir(2)"
    (when (pathnamep x) (setf x (#-scl namestring #+scl posix-namestring x)))
    (or #+ccl (setf (ccl:current-directory) x)
        #+clisp (ext:cd x)
        #+sbcl (sb-posix:chdir x)
        (error "chdir not supported on your implementation")))
  
  
negative.code:     (symbol (typep condition x))
      (function (funcall x condition))
      (string (and (typep condition 'simple-condition)
                   #+(or clozure cmu sbcl scl)
  		 (slot-boundp condition
  			      #+clozure 'ccl::format-control
  			      #+(or cmu scl) 'conditions::format-control
  			      #+sbcl 'sb-kernel:format-control)
                   (ignore-errors (equal (simple-condition-format-control condition) x))))))
  