txt2pre: remove CGI.pm dependency

It's no longer a part of the stock Perl distribution,
and we don't need a whole module for just one function.

diff --git a/Documentation/txt2pre b/Documentation/txt2pre
index ef6a4f3557395825d05fc5818ba56696367ec40e..2dd1597c9a24002ee6f23579c0780da2fad2a93c 100755 (executable)
--- a/Documentation/txt2pre
+++ b/Documentation/txt2pre
@@ -1,16 +1,22 @@
 #!/usr/bin/env perl
-# Copyright (C) 2014-2015 all contributors <meta@public-inbox.org>
-# License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt)
+# Copyright (C) 2014-2016 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 #
 # Stupid script to make HTML from preformatted, utf-8 text versions,
 # only generating links for http(s).  Markdown does too much
 # and requires indentation to output preformatted text.
 use strict;
 use warnings;
-use CGI qw/escapeHTML/;
 use Encode qw/encode/;
 my $str = eval { local $/; <> };
-$str = escapeHTML($str);
+my %xhtml_map = (
+       '"' => '&#34;',
+       '&' => '&#38;',
+       "'" => '&#39;',
+       '<' => '&lt;',
+       '>' => '&gt;',
+);
+$str =~ s/([<>&'"])/$xhtml_map{$1}/ge;
 $str = encode('us-ascii', $str, Encode::HTMLCREF);
 my ($title) = ($str =~ /\A([^\n]+)/);