bug#56222: Emacs 28.1 distribution tarball does not unpack on Solaris 10

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 25 Jun 2022 15:40:08 -0500
> From: Paul Eggert <eggert@cs.ucla.edu>
> 
> The Emacs 28.1 distribution tarball does not unpack correctly on Solaris 
> 10 when using the system-supplied 'tar' program. This is a regression 
> from Emacs 27.2. I didn't pick this up when testing earlier, since I 
> have GNU 'tar' in my PATH (perhaps I shouldn't; oh well). The symptoms are:
> 
>    $ gzip -d <emacs-28.1.tar.gz | tar xf -
>    tar: ././@LongLink: typeflag 'L' not recognized, converting to 
> regular file
>    tar: ././@LongLink: typeflag 'L' not recognized, converting to 
> regular file
>    ...
> 
> The problem is that the Emacs 28.1 tarball (unlike 27.2) has file names 
> longer than 100 bytes. These file names do not fit within traditional 
> 'tar' format. By default, for these files GNU Tar uses a GNU-specific 
> @LongLink extension, designed long ago but not picked up by POSIX, that 
> Solaris 10 tar does not understand.
> 
> A simple workaround is to tell GNU Tar to generate POSIX-standard 
> tarballs instead. I installed the attached patch to Emacs master to fix 
> this, and suggest that it be backported to the Emacs 28 branch if we're 
> planning to generate another Emacs 28 version.

Thanks, I cherry-picked to the emacs-28 branch.

(Yes, there will be at least Emacs 28.2.)