bug#30078: 27.0.50; Use lexical-binding for M-:

[Eli Zaretskii]

> From: Stefan Monnier <monnier@IRO.UMontreal.CA>
> Date: Fri, 12 Jan 2018 11:12:23 -0500
> Cc: 30078@debbugs.gnu.org
> 
> +** Lexical binding is now used when evaluating interactive Elisp forms
> +More specifically, lexical-binding is used for M-:, M-x ielm, as well
> +as in the *scratch* buffer.

Please, not in *scratch*.  Setting variables and then evaluating forms
that use them is very useful there.