Fix missing file&line info in "Unknown defun property" warnings

Fix missing file&line info in "Unknown defun property" warnings

* lisp/emacs-lisp/byte-run.el (defmacro, defun): Use
`macroexp--warn-and-return` rather than `message`.

* lisp/emacs-lisp/macroexp.el: Fix `macroexp--compiling-p`.
(macroexp--warn-and-return): Don't try and detect repetition on forms
like `nil`.
(macroexp-macroexpand): Don't forget to bind `macroexpand-all-environment`.