Replace php_sapi_name() function with PHP_SAPI constant

exact same behavior but faster, shorter
diff --git a/system/core/Input.php b/system/core/Input.php
index 6f184a3..1e67ce1 100644
--- a/system/core/Input.php
+++ b/system/core/Input.php
@@ -872,7 +872,7 @@
 	 */
 	public function is_cli_request()
 	{
-		return (php_sapi_name() === 'cli' OR defined('STDIN'));
+		return (PHP_SAPI === 'cli' OR defined('STDIN'));
 	}
 
 	// --------------------------------------------------------------------