MDL-54729 mod_forum: Deep link highlighting works in IE.

mod/forum/lib.php

@@ -3078,6 +3078,9 @@ function forum_print_post($post, $discussion, $forum, &$cm, $course, $ownpost=fa
 
     // String cache
     static $str;
+    // As we should only have one element with the id of unread we keep track of whether this post is the first
+    // unread post.
+    static $firstunread = true;
 
     $modcontext = context_module::instance($cm->id);
 
@@ -3293,7 +3296,11 @@ function forum_print_post($post, $discussion, $forum, &$cm, $course, $ownpost=fa
             $forumpostclass = ' read';
         } else {
             $forumpostclass = ' unread';
-            $output .= html_writer::tag('a', '', array('name'=>'unread'));
+            // If this is the first unread post then give it an anchor and id of unread.
+            if ($firstunread) {
+                $output .= html_writer::tag('a', '', array('id' => 'unread'));
+                $firstunread = false;
+            }
         }
     } else {
         // ignore trackign status if not tracked or tracked param missing