Rewrite autoloader

lib/Varien/Autoload.php

@@ -57,6 +57,11 @@ static public function register()
      */
     public function autoload($class)
     {
-        return @include str_replace(' ', DIRECTORY_SEPARATOR, ucwords(str_replace('_', ' ', $class))) . '.php';
+        $path = str_replace(['_', '\\', ' '], DIRECTORY_SEPARATOR, $class) . '.php';
+        /** @see https://stackoverflow.com/a/5504486/716029 */
+        $found = stream_resolve_include_path($path);
+        if ($found !== false) {
+            return include $found;
+        }
     }
 }

lib/phpseclib/bootstrap.php

@@ -1,9 +1,9 @@
 <?php
 /**
  * Bootstrapping File for phpseclib
- *
  * @license http://www.opensource.org/licenses/mit-license.html MIT License
  */
+
 if (extension_loaded('mbstring')) {
     // 2 - MB_OVERLOAD_STRING
     if (ini_get('mbstring.func_overload') & 2) {
@@ -13,10 +13,3 @@
         );
     }
 }
-
-spl_autoload_register(function($className) {
-    $parts = explode('\\', $className);
-    if (array_shift($parts) == 'phpseclib') {
-        return include str_replace('\\', DIRECTORY_SEPARATOR, $className) . '.php';
-    }
-});