ifont: Fix empty font glyphs for IE8

The embedded font is included inline in the stylesheets. IE falls back and
tries to load one of the other font sources which was not exported by the web
server. This fix moves the fontello directory to public and add add a
prefix path to the embedded stylesheet.

refs #6417

library/Icinga/Web/LessCompiler.php

@@ -38,15 +38,17 @@ class LessCompiler
 
     /**
      * Create a new instance
+     *
+     * @param   string  $basePath   Provide web base path optional
      */
-    public function __construct()
+    public function __construct($basePath = null)
     {
         require_once 'lessphp/lessc.inc.php';
         $this->lessc = new lessc();
 
         $this->lessc->setVariables(
             array(
-                'baseurl' => '\'' . Zend_Controller_Front::getInstance()->getBaseUrl(). '\''
+                'baseurl' => '\'' . $basePath. '\''
             )
         );
     }

library/Icinga/Web/StyleSheet.php

@@ -11,7 +11,7 @@ use Icinga\Web\LessCompiler;
 class StyleSheet
 {
     protected static $lessFiles = array(
-        '../application/fonts/fontello-ifont/css/ifont-embedded.css',
+        'fonts/fontello-ifont/css/ifont-embedded.less',
         'css/vendor/tipsy.css',
         'css/icinga/defaults.less',
         'css/icinga/layout-colors.less',
@@ -96,7 +96,8 @@ class StyleSheet
             $cache->send($cacheFile);
             return;
         }
-        $less = new LessCompiler();
+
+        $less = new LessCompiler(dirname($_SERVER['PHP_SELF']));
         foreach ($lessFiles as $file) {
             $less->addFile($file);
         }

public/fonts/fontello-ifont/css/ifont-embedded.less

@@ -1,8 +1,8 @@
 @font-face {
   font-family: 'ifont';
-  src: url('../font/ifont.eot?75097146');
-  src: url('../font/ifont.eot?75097146#iefix') format('embedded-opentype'),
-       url('../font/ifont.svg?75097146#ifont') format('svg');
+  src: url('@{baseurl}/fonts/fontello-ifont/font/ifont.eot?75097146');
+  src: url('@{baseurl}/fonts/fontello-ifont/font/ifont.eot?75097146#iefix') format('embedded-opentype'),
+       url('@{baseurl}/fonts/fontello-ifont/ifont.svg?75097146#ifont') format('svg');
   font-weight: normal;
   font-style: normal;
 }

public/fonts/fontello-ifont/icingaweb.md

@@ -0,0 +1,6 @@
+# fontello-ifont has been moved
+
+The font directory has been moved to the public structure because of Internet Explorer version 8 compatibility. The
+common way for browsers is to include the binary embeded font type in the javascript. IE8 falls back and include one of
+the provided font sources. Therefore it is important to have the font files available public and exported by the
+HTTP server.