bug#20445: excessive redisplay / echo area resizing during byte-compilation

[Eli Zaretskii]

> Date: Tue, 28 Apr 2015 19:43:03 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: rgm@gnu.org, 20445@debbugs.gnu.org
> 
> -      (byte-compile-file buffer-file-name)
> +      (let ((byte-compile--interactive t))
> +        (byte-compile-file buffer-file-name))
>       (error "The buffer must be saved in a file first")))

Maybe we should introduce an additional value for resize-mini-windows,
which will never reset the echo area, even if it becomes empty.  Then
we could bind resize-mini-windows to that value in
emacs-lisp-byte-compile.

But I actually am not sure why (message nil) is used as a knob to
control whether echo-area messages are or aren't displayed.  Can you
explain?