General: Patch PHMailer for PHP 7.4 compatibility.

This patches the PHPMailer library in Core to be PHP 7.4 compatible by adding a version check before calling `get_magic_quotes_runtime()`.

Props ayeshrajans, jrf.
See #47783.
Built from https://develop.svn.wordpress.org/trunk@46378


git-svn-id: http://core.svn.wordpress.org/trunk@46177 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-phpmailer.php

@@ -2712,7 +2712,7 @@ class PHPMailer
             if (!self::isPermittedPath($path) or !file_exists($path)) {
                 throw new phpmailerException($this->lang('file_open') . $path, self::STOP_CONTINUE);
             }
-            $magic_quotes = get_magic_quotes_runtime();
+            $magic_quotes = ( PHP_VERSION_ID < 70400 && get_magic_quotes_runtime() ); // WP: Patched for PHP 7.4.
             if ($magic_quotes) {
                 if (version_compare(PHP_VERSION, '5.3.0', '<')) {
                     set_magic_quotes_runtime(false);

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-beta2-46377';
+$wp_version = '5.3-beta2-46378';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.