Fix various compatibility issues with PHP 8

libs/swiftmailer/swift_required.php

@@ -0,0 +1,30 @@
+<?php
+
+/*
+ * This file is part of SwiftMailer.
+ * (c) 2004-2009 Chris Corbyn
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/*
+ * Autoloader and dependency injection initialization for Swift Mailer.
+ */
+
+if (class_exists('Swift', false)) {
+    return;
+}
+
+// Load Swift utility class
+require __DIR__.'/classes/Swift.php';
+
+if (!function_exists('_swiftmailer_init')) {
+    function _swiftmailer_init()
+    {
+        require __DIR__.'/swift_init.php';
+    }
+}
+
+// Start the autoloader and lazy-load the init script to set up dependency injection
+Swift::registerAutoload('_swiftmailer_init');