Third OpenPGP backend: PGG

[Simon Josefsson <jas@extundo.com>]

I added support for PGG in mml2015.el, and added a top-level directory
pgg/ which contains PGG and its dependencies.  When copyright
assignment have been checked, hopefully files can be moved into lisp/.

To use it, just put gnus/pgg into your load-path, Gnus should prefer
PGG over gpg.el and Mailcrypt.

The goal is of course to have OpenPGP simply work out of the box.
Mailcrypt and gpg.el cannot be shipped due to copyright problems.

A few months old discussion relating to this follows...

Lars Magne Ingebrigtsen <larsi@gnus.org> writes:

> Simon Josefsson <jas@extundo.com> writes:
>
>> I'm looking at getting some FSF-owned PGP/GPG interface library to work
>> (since gpg.el now seems officially dead), and it seems as if Daiki Ueno
>> has written one in the SEMI package.  However, it seem to require LUNA (a
>> OO kernel for lisp) and lots of other libraries from APEL/FLIM.  Assuming
>> they are all FSF-owned and that they don't override normal behaviour in
>> emacs/gnus (which has to be verified, I remember old versions of APEL
>> behaving rather badly in this regard), is it OK to add them to Gnus CVS?  
>> It might be quite some files..
>
> It sounds like something a bit separate from Gnus, but Gnus is a nice
> way to test stuff like that, so go ahead and add it to the
> repository.  (It can be removed later if you want to split it out
> into a separate package again.)
>
> However, from my own experiences with the APEL/FLIM code, it tends to
> be quite invasive -- redefines lots of standard functions and stuff,
> so it might be difficult.  It's been quite a while since I looked at
> the code, though.
>
> -- 
> (domestic pets only, the antidote for overdose, milk.)
>    larsi@gnus.org * Lars Magne Ingebrigtsen

Daiki Ueno <ueno@unixuser.org> writes:

>>>>>> In <Pine.LNX.4.44.0205061112340.6648-100000@yxa.extundo.com> 
>>>>>>	Simon Josefsson <jas@extundo.com> wrote:
>
>> > > Hi.  Is copyright on PGG assigned to FSF?  Is the latest version in
>> > > SEMI CVS?  What do you think about adding it to Gnus (and ultimately
>> > > Emacs)?
>
>> > The latest version of PGG is only available on my branch of SEMI.  It
>> > also includes some documentation.  Please get it from:
>> > 
>> >   http://cvs.m17n.org/cgi-bin/viewcvs/semi/?only_with_tag=emiko-1_14
>
>> Thanks, I'll work on integrating this.  Which branch of FLIM and APEL is 
>> your code supposed to work with?
>
> It should work with the latest release of APEL and FLIM.
> They are available on:
> ftp://ftp.m17n.org/pub/mule/apel/apel-10.3.tar.gz
> ftp://ftp.m17n.org/pub/mule/flim/flim-1.14/flim-1.14.3.tar.gz
>
> Regards,
> -- 
> Daiki Ueno