* doc/lispref/variables.texi (Scope): Mention the availability of lexbind.

* doc/lispref/variables.texi (Scope): Mention the availability of lexbind.
(Lexical Binding): New node.
* doc/lispref/eval.texi (Eval): Add `eval's new `lexical' arg.
* lisp/emacs-lisp/cconv.el (cconv-liftwhen): Increase threshold.
(cconv-closure-convert-rec): Convert interactive spec in empty lexenv.
(cconv-analyse-use): Improve unused vars warnings.
(cconv-analyse-form): Analyze interactive spec in empty lexenv.
* lisp/emacs-lisp/bytecomp.el (byte-compile-lambda): Always byte-compile
the interactive spec in lexical-binding mode.
(byte-compile-refresh-preloaded): Don't reload byte-compiler files.
* lisp/custom.el (custom-initialize-default): Use defvar.
(custom-declare-variable): Set the special-variable-p flag.
* lisp/help-fns.el (help-make-usage): Drop leading underscores.
* lisp/dired.el (dired-revert, dired-make-relative): Mark unused args.
(dired-unmark-all-files): Remove unused var `query'.
(dired-overwrite-confirmed): Declare.
(dired-restore-desktop-buffer): Don't use dynamically scoped arg names.
* lisp/mpc.el: Mark unused args.
(mpc--faster-toggle): Remove unused var `songnb'.
* lisp/server.el (server-kill-buffer-running): Move before first use.
* lisp/minibuffer.el: Mark unused args.
* src/callint.c (quotify_arg): Simplify the logic.
(Fcall_interactively): Use lexical binding when evaluating the
interactive spec of a lexically bound function.