Fix error code

build/generate_filelist_xml.php

@@ -33,7 +33,7 @@ $path = dirname(__FILE__).'/';
 // Test if batch mode
 if (substr($sapi_type, 0, 3) == 'cgi') {
 	echo "Error: You are using PHP for CGI. To execute ".$script_file." from command line, you must use PHP for CLI mode.\n";
-	exit;
+	exit(1);
 }
 
 require_once $path."../htdocs/master.inc.php";