```common lisp
(cl:in-package #:sicl-data-and-control-flow)

(defun fdefinition (function-name)
  (sicl-global-environment:fdefinition
   function-name
   sicl-global-environment:*global-environment*))
```

Use function GLOBAL-ENVIRONMENT rather than obsolete special variable.
user
```common lisp
(cl:in-package #:sicl-data-and-control-flow)

(defun fdefinition (function-name)
  (sicl-global-environment:fdefinition
   function-name
   (load-time-value
    (sicl-global-environment:global-environment))))
```
assistant