backtrace patch

[Jeremy Jones <jaj>]

Here is a quick and dirty patch to make option-period in a backtrace
dialog bring up the function definition for the selected function.

(defobfun (window-key-event-handler ccl::*backtrace-dialog-class*) (key)
  (when (eq key #\263)
    (let ((sym (intern (ask (car (dialog-items))
                         (cell-contents (car (selected-cells)))))))
      (unless (edit-definition sym)
        (ed-beep)
        (format t "Function definition for ~s was not found." sym)))))