bug#52329: Fix alignment of makefile-backslash-region

[Stefan Kangas]

Fredrik Bergroth <fbergroth@gmail.com> writes:

> `makefile-backslash-region' is inserting tabs rather than spaces (due to the 
> major mode setting indent-tabs-mode).
> The backslashes won't align properly (unless everyone agrees on a tab-width). 
> I attached a patch that fixes this.

Thanks for the patch.

Could you provide a recipe to reproduce this problem, preferably
starting from "emacs -Q"?