bug#37527: [PATCH] Install C source code for for debugging help

[Eli Zaretskii]

> Cc: Eli Zaretskii <eliz@gnu.org>, 37527@debbugs.gnu.org,
>  Glenn Morris <rgm@gnu.org>
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Mon, 7 Oct 2019 12:48:45 -0700
> 
> Is the emacs-26 branch still active and still being merged from?

It shouldn't be active, we should work only on master now.  Although
if someone makes some doc change there by mistake, it isn't a
catastrophe, it just requires merges that otherwise wouldn't have been
necessary.