Patch derived from discussion at https://savannah.nongnu.org/bugs/?37503

--- texi2html-5.0/texi2html.pl	2010-06-30 17:01:27.000000000 -0500
+++ texi2html-5.0/texi2html.pl	2014-07-09 01:17:57.062990582 -0500
@@ -2589,7 +2589,12 @@
     my $state = shift;
 
     # FIXME this should be done only once, for @documentencoding
-    my $encoding = lc(Texi2HTML::Config::get_conf('DOCUMENT_ENCODING'));
+    my $encoding;
+    my $input_encoding = Texi2HTML::Config::get_conf('documentencoding');
+    if (defined($input_encoding))
+    {
+      $encoding = lc($input_encoding);
+    }
     if (defined($encoding) and $encoding ne '' and exists($Texi2HTML::Config::t2h_encoding_aliases{$encoding}))
     {
        $encoding = $Texi2HTML::Config::t2h_encoding_aliases{$encoding};

Fix failures in test/encodings.

--- texi2html-5.0/texi2html.pl	2014-07-09 01:22:06.000000000 -0500
+++ texi2html-5.0/texi2html.pl	2014-07-10 23:23:47.182097602 -0500
@@ -53,6 +53,7 @@
 # for translations
 #use encoding 'utf8';
 #use utf8;
+binmode STDERR, ':encoding(utf8)';
 
 #
 # According to
guix/refs/?id=9a757283186766aabd9e179ad8516e724ec16fa1'>refs</a><a class='active' href='/guix/log/po/doc/local.mk'>log</a><a href='/guix/tree/po/doc/local.mk?id=9a757283186766aabd9e179ad8516e724ec16fa1'>tree</a><a href='/guix/commit/po/doc/local.mk?id=9a757283186766aabd9e179ad8516e724ec16fa1'>commit</a><a href='/guix/diff/po/doc/local.mk?id=9a757283186766aabd9e179ad8516e724ec16fa1'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/po/doc/local.mk'>
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<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=9a757283186766aabd9e179ad8516e724ec16fa1'>root</a>/<a href='/guix/log/po?id=9a757283186766aabd9e179ad8516e724ec16fa1'>po</a>/<a href='/guix/log/po/doc?id=9a757283186766aabd9e179ad8516e724ec16fa1'>doc</a>/<a href='/guix/log/po/doc/local.mk?id=9a757283186766aabd9e179ad8516e724ec16fa1'>local.mk</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/po/doc/local.mk?id=9a757283186766aabd9e179ad8516e724ec16fa1&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-09-29 15:33:20 +0200'>2020-09-29</span></td><td><a href='/guix/commit/po/doc/local.mk?id=c69156fc89ac46b7bebfb35e6ad205ed1b2e6df6'>nls: Fix documentation pot generation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/doc/local.mk: Fix POT_OPTIONS to properly assign copyright and
define the proper license.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2020-03-06 20:50:18 +0000'>2020-03-06</span></td><td><a href='/guix/commit/po/doc/local.mk?id=895e6e8af657d28527f7cccf68eab7319f50fba5'>doc: Fix build of German Cookbook translation.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a follow-up to f98e83a17fa30587520e858231ec9c61f3624ecd.
See &lt;https://lists.gnu.org/archive/html/guix-devel/2020-03/msg00095.html&gt;.
Reported there by Vagrant Cascadian &lt;vagrant@debian.org&gt;.

* po/doc/local.mk (DOC_COOKBOOK_PO_FILES): Use correct file name.
(doc-po-update-cookbook-%): Use correct PO file name.
</span></span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2020-02-17 06:52:11 +0000'>2020-02-17</span></td><td><a href='/guix/commit/po/doc/local.mk?id=f98e83a17fa30587520e858231ec9c61f3624ecd'>doc: Add German Cookbook translation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/local.mk (info_TEXINFOS): Add guix-cookbook.de.texi.
(TRANSLATED_INFO): Add guix-cookbook.de.texi.
* po/doc/guix-cookbook.de.po: New file.
* po/doc/local.mk (DOC_COOKBOOK_PO_FILES): Add guix-cookbook.de.po.
</span></span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2019-09-18 11:38:14 +0200'>2019-09-18</span></td><td><a href='/guix/commit/po/doc/local.mk?id=7bc46ecc34ceb042ff890e5d306d0a2a736e891d'>doc: Add Guix Cookbook.</a><span class='msg-avail'>...<span class='msg-tooltip'>* .gitignore: Update ignore list.
* Makefile.am (assert-no-store-file-names): Exclude the cookbook.
* bootstrap: Generate po files for cookbook translations.
* doc/guix-cookbook.texi: New file.
* doc/local.mk (info_TEXINFOS): Add it; add a rule to build cookbook
translations.
* po/doc/local.mk (DOC_COOKBOOK_PO_FILES): New variable.
(EXTRA_DIST): Add cookbook pot file and po files.
(doc-po-update-cookbook-%): New target.
(doc-pot-update): Also update cookbook pot file.
(doc-po-update): Also update cookbook po files.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2019-05-13 10:46:03 +0200'>2019-05-13</span></td><td><a href='/guix/commit/po/doc/local.mk?id=3bac7e6495934de9913e6186d954d1331883e064'>doc: Add Russian translation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/local.mk (info_TEXINFOS): Add guix.ru.texi.
(TRANSLATED_INFO): Add {guix,contributing}.ru.texi.
* po/doc/local.mk (DOC_PO_FILES): Add guix-manual.ru.po.
* po/doc/guix-manual.ru.po: New file.
</span></span></td><td>Ludovic Courtès</td></tr>