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

[Eli Zaretskii]

> Cc: Michael Albinus <michael.albinus@gmx.de>, rgm@gnu.org,
>  37527@debbugs.gnu.org
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Tue, 21 Jan 2020 01:13:53 -0800
> 
> --- a/src/emacs.c
> +++ b/src/emacs.c
> @@ -522,6 +522,7 @@ init_cmdargs (int argc, char **argv, int skip_args, char 
> const *original_pwd)
>             if (!NILP (etc_exists))
>               {
>                    Vinstallation_directory = Ffile_name_as_directory (dir);
> +               Vsource_directory = Vinstallation_directory;
>                 break;
>               }
>           }
> @@ -547,6 +548,7 @@ init_cmdargs (int argc, char **argv, int skip_args, char 
> const *original_pwd)
>               {
>                 tem = Fexpand_file_name (build_string (".."), dir);
>                    Vinstallation_directory = Ffile_name_as_directory (tem);
> +               Vsource_directory = Vinstallation_directory;
>                 break;
>               }

Bother.  Should we really step on source-directory like that?  What if
the original source tree still exists?  Maybe it would be safer to
introduce a new variable, say, install-source-directory?