Added links to "a duplicate of" bug ids.

bug_form.pl

@@ -33,6 +33,8 @@ sub quoteUrls {
     my $text = shift;		# Take a copy; don't modify in-place.
     return $text unless $text;
 
+    my $base = Param('urlbase');
+
     my $protocol = join '|',
     qw(afs cid ftp gopher http https mid news nntp prospero telnet wais);
 
@@ -71,10 +73,15 @@ sub quoteUrls {
         my $num = $2;
         $item = value_quote($item); # Not really necessary, since we know
                                 # there's no special chars in it.
-        my $base = Param('urlbase');
         $item = qq{<A HREF="${base}show_bug.cgi?id=$num">$item</A>};
         $things[$count++] = $item;
     }
+    while ($text =~ s/\*\*\* This bug has been marked as a duplicate of (\d+) \*\*\*/"##$count##"/ei) {
+        my $item = $&;
+        my $num = $1;
+        $item =~ s@\d+@<A HREF="${base}show_bug.cgi?id=$num">$num</A>@;
+        $things[$count++] = $item;
+    }
     while ($text =~ s/Created an attachment \(id=(\d+)\)/"##$count##"/e) {
         my $item = $&;
         my $num = $1;