Fix byte-compiler pacification for declare-function

Problem reported by Michael Heerdegen in:
http://lists.gnu.org/archive/html/emacs-devel/2016-05/msg00590.html
* lisp/emacs-lisp/bytecomp.el:
(byte-compile-macroexpand-declare-function):
Revert signature to previous value.
* lisp/subr.el (declare-function): Change signature to
match the reverted signature used in the byte compiler.

lisp/emacs-lisp/bytecomp.el

@@ -2958,24 +2958,23 @@ for symbols generated by the byte compiler itself."
 	 (list body))))
 
 ;; Special macro-expander used during byte-compilation.
-(defun byte-compile-macroexpand-declare-function (fn file &optional arglist
-                                                     fileonly)
-  (let ((gotargs (listp arglist))
+(defun byte-compile-macroexpand-declare-function (fn file &rest args)
+  (let ((gotargs (and (consp args) (listp (car args))))
 	(unresolved (assq fn byte-compile-unresolved-functions)))
     (when unresolved	      ; function was called before declaration
       (if (and gotargs (byte-compile-warning-enabled-p 'callargs))
-	  (byte-compile-arglist-warn fn arglist nil)
+	  (byte-compile-arglist-warn fn (car args) nil)
 	(setq byte-compile-unresolved-functions
 	      (delq unresolved byte-compile-unresolved-functions))))
     (push (cons fn (if gotargs
-		       (list 'declared arglist)
+		       (list 'declared (car args))
 		     t))                     ; Arglist not specified.
 	  byte-compile-function-environment))
   ;; We are stating that it _will_ be defined at runtime.
   (setq byte-compile-noruntime-functions
         (delq fn byte-compile-noruntime-functions))
   ;; Delegate the rest to the normal macro definition.
-  (macroexpand `(declare-function ,fn ,file ,arglist ,fileonly)))
+  (macroexpand `(declare-function ,fn ,file ,@args)))
 
 
 ;; This is the recursive entry point for compiling each subform of an