tempdir's CLEANUP flag

Since elsewhere in this thread you wrote this needs to work on Windows, let me quote "DBD::SQLite And File::Temp" from the DBD::SQLite documentation:

CLEANUP may not work unless a database is disconnected

When you set CLEANUP option to true when you create a temporary directory with tempdir() or newdir(), you may have to disconnect databases explicitly before the temporary directory is gone (notably under MS Windows).