Misc fixes, and use lexical-binding in more files.

* lisp/subr.el (letrec): New macro.
(with-wrapper-hook): Move from lisp/simple.el and don't use CL.
* simple.el (with-wrapper-hook): Move with-wrapper-hook to subr.el.
* lisp/help-fns.el (help-function-arglist): Handle subroutines as well.
(describe-variable): Use special-variable-p to filter completions.
* lisp/emacs-lisp/macroexp.el (macroexpand-all-1): Don't expand `declare'
in defmacros.
* lisp/emacs-lisp/cconv.el (cconv-convert, cconv-analyse-form):
Handle `declare'.
* lisp/emacs-lisp/cl.el (pushnew): Silence unfixable warning.
* lisp/emacs-lisp/cl-macs.el (defstruct, define-compiler-macro):
Mark unused arg as unused.
* lisp/emacs-lisp/byte-opt.el (byte-optimize-lapcode): Use memq.
* lisp/emacs-lisp/autoload.el (make-autoload): Don't assume the macro's
first sexp is a list.
(autoload-generate-file-autoloads): Improve error message.
* lisp/emacs-lisp/advice.el (ad-arglist): Use help-function-arglist
to understand the new byte-code arg format.
* lisp/vc/smerge-mode.el:
* lisp/vc/log-view.el:
* lisp/vc/log-edit.el:
* lisp/vc/cvs-status.el:
* lisp/uniquify.el:
* lisp/textmodes/css-mode.el:
* lisp/textmodes/bibtex-style.el:
* lisp/reveal.el:
* lisp/newcomment.el:
* lisp/emacs-lisp/smie.el:
* lisp/abbrev.el: Use lexical-binding.
* src/eval.c (Fprog1, Fprog2): Simplify and use XCDR/XCAR.
(Fdefvar): Remove redundant SYMBOLP check.
(Ffunctionp): Don't signal an error for undefined aliases.
* doc/lispref/variables.texi (Converting to Lexical Binding): New node.

lisp/emacs-lisp/autoload.el

@@ -137,7 +137,7 @@ or macro definition or a defcustom)."
             ;; Special case to autoload some of the macro's declarations.
             (let ((decls (nth (if (stringp (nth 3 form)) 4 3) form))
                   (exps '()))
-              (when (eq (car decls) 'declare)
+              (when (eq (car-safe decls) 'declare)
                 ;; FIXME: We'd like to reuse macro-declaration-function,
                 ;; but we can't since it doesn't return anything.
                 (dolist (decl decls)
@@ -471,7 +471,8 @@ Return non-nil if and only if FILE adds no autoloads to OUTFILE
                                    (marker-buffer output-start)))
                               (autoload-print-form autoload)))
                         (error
-                         (message "Error in %s: %S" file err)))
+                         (message "Autoload cookie error in %s:%s %S"
+                                  file (count-lines (point-min) (point)) err)))
 
                     ;; Copy the rest of the line to the output.
                     (princ (buffer-substring