Display an error message if the include plugin could not be loaded.

This prevents a crash/blank page if the include plugin is not installed or disabled.

lang/de/lang.php

@@ -9,5 +9,6 @@
 // custom language strings for the plugin
 $lang['readmore']   = '→ Weiter lesen...';
 $lang['nopagemsg']  = 'randominc: keine Seite gefunden.';
+$lang['plugin_include_failure'] = 'randominc: das include Plugin konnte nicht geladen werden. Bitte aktivieren oder installieren Sie das include Plugin.';
 
 //Setup VIM: ex: et ts=2 enc=utf-8 :

lang/en/lang.php

@@ -9,5 +9,6 @@
 // custom language strings for the plugin
 $lang['readmore']   = '→ Read more...';
 $lang['nopagemsg']  = 'randominc: no page found.';
+$lang['plugin_include_failure'] = 'randominc: could not load include plugin. Please install or enable the include plugin.';
 
 //Setup VIM: ex: et ts=2 enc=utf-8 :

syntax.php

@@ -123,7 +123,14 @@ function render($format, Doku_Renderer $renderer, $data) {
         $this->getFlags($flags, $flagsarray);
 
         if (!$this->helper)
+        {
             $this->helper = plugin_load('helper', 'include');
+            if (!$this->helper)
+            {
+                msg($this->getLang('plugin_include_failure'), -1);
+                return true;
+            }
+        }
         $flags = $this->helper->get_flags($flags);
 
         $pages = $this->helper->_get_included_pages($mode, $page, $sect, $parent_id, $flags);