support/download: make the svn backend more reproducible

support/download: make the svn backend more reproducible

Since c043ecb20ce6 (support/download: change format of archives
generated from svn), the svn backend uses the generic helper to
create reproducible archives.

That helper really does its job as expected, but the svn backend
is flawed in two ways:

  - the first, most obvious breakage happens with versions older
    than 1.9, as they do not support the '--show-item' option
    for the 'info' action;

  - the second is more involved, in that svn will by default
    expand the old, legacy, deprecated, cumbersome CVS-style
    keywords, in the form of revision marks like '$Date$' in a
    C-style comment in a source file. These replacements are
    done on checkout as well as on export, and they use local
    settings, like the local locale and timezone.

    This means that two people with different settings, will get
    different sources when the svn-checkout or svn-export the same
    revision from the same tree...

    Needless to say that this is not very reproducible...

While the first is easily solved, the second is more involved.

We need to ensure that what source is used initially to compute
the hash, will also be the source that are used to check the hash.

There are basically two solutions:

 1. we ensure the same environment, by forcing the timezone and
    the locale to arbitrary values

 2. we disable keyword expansion

For the first solution, this still leaves the possibility that we
miss some environment settings that have an impact on the keyword
expansion. It would mean that Yann's settings be used, as he did
introduce the hash for the only svn-downloaded package we have,
avrdude, settings which are:
    TZ=Europe/Paris
    LC_TIME="en_US.UTF-8"
    LC_COLLATE="en_GB.UTF-8"
    LC_MONETARY="fr_FR.utf8"
    LC_NUMERIC="fr_FR.utf8"

The second option means that the generated archives change. That
means we'd have to bump the archive version for svn downloads, and
that we update the hashes for all the svn-downloaded packages.

We chose to go with the second option, because this is what really
makes more sense, rather than hard-coding arbitrary values in the
environment. And we also have only one svn-downloaded package,
avrdude.

And thus, we're reaching the trigger for this change: avrdude is
impacted by the CVS-keyword expansion issue:

    https://svn.savannah.gnu.org/viewvc/avrdude/trunk/avrdude/atmel-docs/EDBG/common/jquery/layout/jquery.layout.js?revision=1396&view=markup

which would give two different files when checked out on different
machines:

    diff -durN foo/avrdude-r1450/avrdude/atmel-docs/EDBG/common/jquery/layout/jquery.layout.js bar/avrdude-r1450/avrdude/atmel-docs/EDBG/common/jquery/layout/jquery.layout.js
    --- foo/avrdude-r1450/avrdude/atmel-docs/EDBG/common/jquery/layout/jquery.layout.js 2020-09-22 09:36:45.000000000 +0200
    +++ bar/avrdude-r1450/avrdude/atmel-docs/EDBG/common/jquery/layout/jquery.layout.js 2020-09-22 09:36:45.000000000 +0200
    @@ -1,6 +1,6 @@
     /**
      * @preserve jquery.layout 1.3.0 - Release Candidate 30.51
    - * $Date: 2015-11-02 22:13:28 +0100 (Mon, 02 Nov 2015) $
    + * $Date: 2015-11-02 21:13:28 +0000 (Mon, 02 Nov 2015) $
      * $Rev: 303005 $
      *
      * Copyright (c) 2012
    @@ -4718,7 +4718,7 @@

     /**
      * jquery.layout.state 1.0
    - * $Date: 2015-11-02 22:13:28 +0100 (Mon, 02 Nov 2015) $
    + * $Date: 2015-11-02 21:13:28 +0000 (Mon, 02 Nov 2015) $
      *
      * Copyright (c) 2010
      *   Kevin Dalman (http://allpro.net)
    @@ -5074,7 +5074,7 @@

     /**
      * jquery.layout.buttons 1.0
    - * $Date: 2015-11-02 22:13:28 +0100 (Mon, 02 Nov 2015) $
    + * $Date: 2015-11-02 21:13:28 +0000 (Mon, 02 Nov 2015) $
      *
      * Copyright (c) 2010
      *   Kevin Dalman (http://allpro.net)
    @@ -5356,7 +5356,7 @@

     /**
      * jquery.layout.browserZoom 1.0
    - * $Date: 2015-11-02 22:13:28 +0100 (Mon, 02 Nov 2015) $
    + * $Date: 2015-11-02 21:13:28 +0000 (Mon, 02 Nov 2015) $
      *
      * Copyright (c) 2012
      *   Kevin Dalman (http://allpro.net)

So we also update the hash for avrdude.

Fixes:
    http://autobuild.buildroot.org/results/e3b/e3b0508047f32008ebfa83c5255ec5994b6af120/ (time issue)
    http://autobuild.buildroot.org/results/48e/48e78e84b425e79cdb98c16ab40247a0fa7e9676/ (keyword expansion issue)

Reported-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Vincent Fazio <vfazio@xes-inc.com>
Cc: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>