i18n enhancements:

Currently, template directories are found in the order listed in the
Language option in validator.conf.

Enhanced patches no longer use the Language option.

By referring to the Accept-Languages header value of the browser, the
template directory is found in Accept-Language order.

For examples:

For example, if Accept-Languages is:

```Accept-Langau: en-GB, en: q = 0.7, en: q = 0.3```

The validator will find the template in the following order:

1. template/ko_KR
1. template/ko
1. tempalte/en-US
1. template/en

If there is no template corresponding to Accept-Languages, template /
en_US will be used.

htdocs/config/validator.conf

@@ -79,10 +79,6 @@ Max Recursion = 0
 # Email address of the maintainer of this service.
 Maintainer = www-validator@w3.org
 
-# Localization
-# only English available for now
-Languages = en
-
 # 
 # Optional additional information or identifier to include in the User-Agent Header
 # W3C has found it helpful to include a link in the instances they run explaining the service

httpd/cgi-bin/check

@@ -301,31 +301,33 @@ $File->{"Default DOCTYPE"}->{"XHTML"} = 'XHTML 1.0 Transitional';
 # 3) English by default
 my $lang = $q->param('lang') || '';
 my @localizations;
-foreach my $lang_available (@{$CFG->{Languages}}) {
-    if ($lang eq $lang_available) {
+my @accept_languages = split(/,/, $q->http('Accept-Language'));
+foreach my $aclang (@accept_languages) {
+    if ($lang eq $aclang) {
 
         # Requested language (from parameters) is available, just use it
         undef @localizations;
         last;
     }
-    push @localizations,
-        [
-        $lang_available, 1,               'text/html', undef,
-        'utf-8',         $lang_available, undef
-        ];
-}
 
-# If language is not chosen yet, use HTTP-based negotiation
-if (@localizations) {
-    require HTTP::Negotiate;
-    $lang = HTTP::Negotiate::choose(\@localizations);
+    my $tmp_lang = $aclang;
+    $tmp_lang =~ s/;q=.*//g if ($aclang =~ /;q=/);
+    $tmp_lang =~ s/-/_/g;
+    push @localizations, $tmp_lang;
 }
+push @localizations, 'en_US' if (@localizations);
 
-# HTTP::Negotiate::choose may return undef e.g if sent Accept-Language: en;q=0
-$lang ||= 'en_US';
-
-if ($lang eq "en") {
-    $lang = 'en_US';    # legacy
+# looking for template directory with accept-language order
+my $loop_limit = 20;
+while (! -f "$CFG->{Paths}->{Templates}/${lang}/header.tmpl") {
+    foreach my $nego (@localizations) {
+        if (-f "$CFG->{Paths}->{Templates}/${nego}/header.tmpl") {
+            $lang = $nego;
+            last;
+        }
+    }
+    $loop_limit--;
+    last if ($loop_limit == 0);
 }
 
 $File->{Template_Defaults} = {