Made Environment Support optional. Comment out or delete the constant to stop environment checks.
diff --git a/system/core/Loader.php b/system/core/Loader.php
index 278a868..e75805d 100644
--- a/system/core/Loader.php
+++ b/system/core/Loader.php
@@ -872,12 +872,12 @@
 					// We test for both uppercase and lowercase, for servers that
 					// are case-sensitive with regard to file names. Check for environment
 					// first, global next
-					if (file_exists($path .'config/'.ENVIRONMENT.'/'.strtolower($class).EXT))
+					if (defined('ENVIRONMENT') AND file_exists($path .'config/'.ENVIRONMENT.'/'.strtolower($class).EXT))
 					{
 						include_once($path .'config/'.ENVIRONMENT.'/'.strtolower($class).EXT);
 						break;
 					}
-					elseif (file_exists($path .'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).EXT))
+					elseif (defined('ENVIRONMENT') AND file_exists($path .'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).EXT))
 					{
 						include_once($path .'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).EXT);
 						break;
@@ -965,7 +965,7 @@
 	 */
 	function _ci_autoloader()
 	{
-		if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/autoload'.EXT))
+		if (defined('ENVIRONMENT') AND file_exists(APPPATH.'config/'.ENVIRONMENT.'/autoload'.EXT))
 		{
 			include_once(APPPATH.'config/'.ENVIRONMENT.'/autoload'.EXT);
 		}