fix links in generated HTML documentation

Invoke installhtml in the right way for it to generate relative links.
Fix installhtml's code for creating relative links in the index for
split documents.  Update Pod::Html's section name transformer to
match the actual output seen via Pod::Simple::XHTML.  Incidentally
update split-on-head code for the new style of HTML generated by
Pod::Simple::XHTML.  Fixes [perl #110056].

Makefile.SH

@@ -1204,7 +1204,6 @@ install.html: all installhtml
 	${LOCAL_PERL} installhtml   \\
       --podroot=. --podpath=. --recurse  \\
       --htmldir=\$(privlib)/html   \\
-      --htmlroot=\$(privlib)/html  \\
       --splithead=pod/perlipc     \\
       --splititem=pod/perlfunc    \\
       --ignore=Porting/Maintainers.pm,Porting/pumpkin.pod,Porting/repository.pod \\

ext/Pod-Html/lib/Pod/Html.pm

@@ -5,7 +5,7 @@ require Exporter;
 our $VERSION = 1.23;
 our @ISA = qw(Exporter);
 our @EXPORT = qw(pod2html htmlify);
-our @EXPORT_OK = qw(anchorify);
+our @EXPORT_OK = qw(anchorify relativize_url);
 
 use Carp;
 use Config;
@@ -661,19 +661,12 @@ sub html_escape {
 
 #
 # htmlify - converts a pod section specification to a suitable section
-# specification for HTML. Note that we keep spaces and special characters
-# except ", ? (Netscape problem) and the hyphen (writer's problem...).
+# specification for HTML.  We adopt the mechanism used by the formatter
+# that we use.
 #
 sub htmlify {
     my( $heading) = @_;
-    $heading =~ s/(\s+)/ /g;
-    $heading =~ s/\s+\Z//;
-    $heading =~ s/\A\s+//;
-    # The hyphen is a disgrace to the English language.
-    # $heading =~ s/[-"?]//g;
-    $heading =~ s/["?]//g;
-    $heading = lc( $heading );
-    return $heading;
+    return Pod::Simple::XHTML->can("idify")->(undef, $heading, 1);
 }
 
 #
@@ -801,7 +794,7 @@ sub resolve_pod_page_link {
         # then $self->htmlroot eq '' (by definition of htmlfileurl) so
         # $self->htmldir needs to be prepended to link to get the absolute path
         # that will be relativized
-        $url = relativize_url(
+        $url = Pod::Html::relativize_url(
             File::Spec::Unix->catdir(Pod::Html::_unixify($self->htmldir), $url),
             $self->htmlfileurl # already unixified
         );
@@ -810,6 +803,8 @@ sub resolve_pod_page_link {
     return $url . ".html$section";
 }
 
+package Pod::Html;
+
 #
 # relativize_url - convert an absolute URL to one relative to a base URL.
 # Assumes both end in a filename.

ext/Pod-Html/t/anchorify.t

@@ -23,18 +23,18 @@ foreach $i (0..$#poddata) {
     $heads{anchorify($1)} = 1 if $poddata[$i] =~ /=head[1-6]\s+(.*)/;
 }
 my %expected = map { $_ => 1 } qw(
-    name
-    description
-    subroutine
-    error
-    method
-    has_a_wordspace
-    hastrailingwordspace
-    hasleadingwordspace
-    has_extra_internalwordspace
-    hasquotes
-    hasquestionmark
-    has_hyphen_and_space
+    NAME
+    DESCRIPTION
+    Subroutine
+    Error
+    Method
+    Has_A_Wordspace
+    HasTrailingWordspace
+    HasLeadingWordspace
+    Has_Extra_InternalWordspace
+    Has_Quotes
+    Has_QuestionMark
+    Has_Hyphen_And_Space
 );
 is_deeply(
     \%heads,

installhtml

@@ -7,7 +7,7 @@ use Config;		# for config options in the makefile
 use File::Spec::Functions qw(rel2abs no_upwards);
 use Getopt::Long;	# for command-line parsing
 use Cwd;
-use Pod::Html 'anchorify';
+use Pod::Html 1.23 qw(anchorify relativize_url);
 
 =head1 NAME
 
@@ -240,10 +240,10 @@ foreach my $dir (@splithead) {
     $/ = "";
     my @data = ();
     while (<H>) {
-	last if /name="name"/i;
+	last if m!<h1 id="NAME">NAME</h1>!;
 	$_ =~ s{href="#(.*)">}{
-	    my $url = "$pod/$1.html" ;
-	    $url = Pod::Html::relativize_url( $url, "$file.html" )
+	    my $url = "$file/@{[anchorify(qq($1))]}.html" ;
+	    $url = relativize_url( $url, "$file.html" )
 	    if ( ! defined $Options{htmlroot} || $Options{htmlroot} eq '' );
 	    "href=\"$url\">" ;
 	}egi;
@@ -254,7 +254,7 @@ foreach my $dir (@splithead) {
     # now rewrite the file
     open(H, '>', "$file.html") ||
 	die "$0: error opening $file.html for output: $!\n";
-    print H "@data", "\n";
+    print H @data, "</body>\n\n</html>\n\n\n";
     close(H);
 }
 
@@ -321,9 +321,9 @@ sub create_index {
 		m#<h1 id="NAME">NAME</h1>\s*<p>\s*(\S+)\s+-\s+(\S.*?\S)</p>#);
 	defined $lcp1 or die "$0: can't find NAME section in $dir/$file\n";
 
-	my $url= "$pod/$file" ;
+	my $url= "$dir/$file" ;
 	if ( ! defined $Options{htmlroot} || $Options{htmlroot} eq '' ) {
-	    $url = Pod::Html::relativize_url( "$pod/$file", $html ) ;
+	    $url = relativize_url( $url, $html ) ;
 	}
 
 	print HTML qq(<DT><A HREF="$url">);