Consider also that current directory . is no more included in @INC in newer Perl version for security reasons: you can include it with use lib '.'

While correct, the way I understood the question is that the working directory is changing, so I don't think that would help here - but this pattern would, which I've used many times:

use FindBin;
use lib $FindBin::Bin;
use Routines;
[download]