Unify the directory separator for `TMP_DIR`

see #5370

diff --git a/wcfsetup/install/files/lib/util/FileUtil.class.php b/wcfsetup/install/files/lib/util/FileUtil.class.php
index 0586d99adaf30a41f05b4ca652eaf8b38bc61eb9..351a699d2d2f7c7e398204acae92496fdefa84a7 100644 (file)
--- a/wcfsetup/install/files/lib/util/FileUtil.class.php
+++ b/wcfsetup/install/files/lib/util/FileUtil.class.php
@@ -39,7 +39,7 @@ final class FileUtil
      */
     public static function getTempFolder(): string
     {
-        $path = WCF_DIR . 'tmp/';
+        $path = self::unifyDirSeparator(WCF_DIR . 'tmp/');
 
         if (\is_file($path)) {
             // wat