Support `cl-defstruct' in autoloads

* lisp/emacs-lisp/autoload.el (make-autoload): Add `cl-defstruct' to
"complex cases" list.

* lisp/emacs-lisp/cl-macs.el (cl-defstruct): Add :autoload-end to
limit what is declared in autoloads.el for a defstruct.

lisp/emacs-lisp/autoload.el

@@ -165,7 +165,7 @@ expression, in which case we want to handle forms differently."
                        define-globalized-minor-mode defun defmacro
 		       easy-mmode-define-minor-mode define-minor-mode
                        define-inline cl-defun cl-defmacro cl-defgeneric
-                       pcase-defmacro))
+                       cl-defstruct pcase-defmacro))
            (macrop car)
 	   (setq expand (let ((load-file-name file)) (macroexpand form)))
 	   (memq (car expand) '(progn prog1 defalias)))

lisp/emacs-lisp/cl-macs.el

@@ -3006,6 +3006,7 @@ Supported keywords for slots are:
     `(progn
        (defvar ,tag-symbol)
        ,@(nreverse forms)
+       :autoload-end
        ;; Call cl-struct-define during compilation as well, so that
        ;; a subsequent cl-defstruct in the same file can correctly include this
        ;; struct as a parent.