Use push, with-current-buffer, dolist, ...

Use push, with-current-buffer, dolist, ...
(byte-compile-const-variables): New var.
(byte-compile-close-variables): Reset it.
(byte-compile-file-form-defvar, byte-compile-defvar): Update it.
(byte-compile-const-symbol-p): Now arg `value' to check defconsts.
(byte-compile-variable-ref): Use it and improve warning message.
(byte-compile-check-lambda-list): Use byte-compile-const-symbol-p.
(byte-compile-lapcode): Remove unused vars.
(byte-compile-eval): Fix thinko in handling of old-autoloads.
(byte-recompile-directory): Use the expanded form for directory.
(byte-compile-track-mouse): Use modern backquote syntax.
(byte-compile-defvar): Detect and properly handle (defconst a).
(byte-compile-defalias-warn): Remove unused arg `alias'.
(byte-compile-defalias): Update call.