bug#8968: arc-mode 7z writing support

[Jason Rumney]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Juri Linkov <juri@jurta.org>
>> Date: Fri, 08 Jul 2011 03:09:51 +0300
>> 
>> As reported in http://thread.gmane.org/gmane.emacs.devel/136578/focus=136670
>> on cygwin the program name is "p7zip".  But I can't confirm this fact,
>> so I'm closing this feature request at its current state with the
>> program name "7z".
>
> In fact, I think any GNU/Linux system that cares about avoiding
> non-free software will have only p7zip, not 7z.  That's because
> current releases of 7z are not Free Software, whereas p7zip uses the
> free-software subset of the 7z algorithms.

All GNU/Linux systems will have only p7zip, as that is the ported
version of 7-zip. 7z is only available for Windows, and comes with two
command line binaries - 7za.exe, which is Free Software, and 7z.exe
which is not (due to unRAR support).