title: Suppress warning for function arguments not used in LISP
body: <p>In lisp, I need to define a set of functions, all with the same number of arguments.
  However, the functions may or may not use all the arguments, leading to a spur of warning messages. For example:</p>
  
  <pre><code>(defun true (X Y) X)
  [...]
  ; caught STYLE-WARNING:
  ;   The variable Y is defined but never used.
  </code></pre>
  
  <p>Is there a way to warn the compiler that is was intended?</p>