Style warning about unused __data variable.

[markcox80]

The example below generates a style warning about the unused variable __data.

(eval-when (:compile-toplevel :load-toplevel :execute)
  (asdf:load-system "cl-template"))

(defpackage "EXAMPLE"
  (:use "COMMON-LISP"))
(in-package "EXAMPLE")

(defun test ()
  (let ((fn (cl-template:compile-template "hey")))
    (funcall fn nil)))

; cl-user> (example::test)
; in: lambda (cl-template::__data)
;     (LAMBDA (CL-TEMPLATE::__DATA)
;       (MACROLET ((@ (VAR)
;                    `(GETF CL-TEMPLATE::__DATA ,#)))
;         (WITH-OUTPUT-TO-STRING (#:G620) (WRITE-STRING "hey" #:G620))))
; 
; caught style-warning:
;   The variable cl-template::__data is defined but never used.
; 
; compilation unit finished
;   caught 1 STYLE-WARNING condition

It would be great if you could add (declare ignorable __data) to compile-template.

Thanks