su: Change the HOME enviroment variable on login

Author: https://github.com/cqundefine
Commit: https://github.com/SerenityOS/serenity/commit/4054c35e9a
Pull-request: https://github.com/SerenityOS/serenity/pull/13439
Issue: https://github.com/SerenityOS/serenity/issues/13436

Userland/Utilities/su.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, Undefine <undefine@undefine.pl>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -48,6 +49,8 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
     TRY(Core::System::pledge("stdio exec"));
 
+    TRY(Core::System::setenv("HOME"sv, account.home_directory(), true));
+
     execl(account.shell().characters(), account.shell().characters(), nullptr);
     perror("execl");
     return 1;