diff --git a/main/inc/lib/main_api.lib.php b/main/inc/lib/main_api.lib.php
index 7b5e9ccdea..b881ed7fc8 100644
--- a/main/inc/lib/main_api.lib.php
+++ b/main/inc/lib/main_api.lib.php
@@ -169,6 +169,11 @@ define('DIR_HOTPOTATOES','/HotPotatoes_files');
 // true whether the server runs on Windows OS, false otherwise.
 define ('IS_WINDOWS_OS', api_is_windows_os());
 
+// Checks for installed optional php-extensions.
+define('INTL_INSTALLED', function_exists('intl_get_error_code'));	// intl extension (from PECL), it is installed by default as of PHP 5.3.0
+define('ICONV_INSTALLED', function_exists('iconv'));				// iconv extension, for PHP5 on Windows it is installed by default.
+define('MBSTRING_INSTALLED', function_exists('mb_strlen'));			// mbstring extension.
+
 /*
 ==============================================================================
 		MAIN API EXTENSIONS
diff --git a/main/inc/lib/multibyte_string_functions.lib.php b/main/inc/lib/multibyte_string_functions.lib.php
index af3159f831..11365cf910 100644
--- a/main/inc/lib/multibyte_string_functions.lib.php
+++ b/main/inc/lib/multibyte_string_functions.lib.php
@@ -37,18 +37,11 @@
  * When encodings to be used are not supported by mbstring, this library
  * is able to exploit the PHP iconv extesion, which in this case should
  * be activated too.
+ * 
+ * 5. For improved sorting of multibyte strings the library uses the intl
+ * php-extension if it is installed.
  */
 
-/**
- * ----------------------------------------------------------------------------
- * Constants
- * ----------------------------------------------------------------------------
- */
-
-define('INTL_INSTALLED', function_exists('intl_get_error_code'));	// intl extension (from PECL), it is installed by default as of PHP 5.3.0
-define('ICONV_INSTALLED', function_exists('iconv'));				// iconv extension, for PHP5 on Windows it is installed by default.
-define('MBSTRING_INSTALLED', function_exists('mb_strlen'));			// mbstring extension.
-
 /**
  * ----------------------------------------------------------------------------
  * A safe way to calculate binary lenght of a string (as number of bytes)