bug#28008: 25.2; Resume kmacro definition errors C-u C-u <F3>

[Eli Zaretskii]

> From: Allen Li <vianchielfaura@gmail.com>
> Date: Tue, 19 Sep 2017 00:42:21 -0700
> Cc: Eli Zaretskii <eliz@gnu.org>, 28008@debbugs.gnu.org
> 
> Actually, to fix case D.2 (where undefined keys exit kmacro definition
> without saving), all that is needed is a short Emacs Lisp change.
> This keeps the behavior of a bare C-g keyboard-abort of not saving the
> kmacro.
> 
> [PATCH] Make undefined keys exit and save kmacro definition
> 
> * lisp/subr.el (undefined): Error out of kmacro definition.

Thanks, pushed to the release branch.