Abigail's solution works -- mostly.

I had to toss the use warnings; pragma, as the module isn't included in Perl 5.005_03.

The situation now stands as follows:

• On a 5.005_03 installation, the script runs to completion with no nasty messages.
  
• On a 5.6.0 installation, the script yields this warning message:

  Prototype mismatch: sub File::Spec::Unix::rel2abs ($;$;) vs none at /w
  +onko/share/jwd/lib/perl/File/Spec/Unix.pm line 447.
  [download]

Any suggestion as to how to eliminate this? Explanation as to its cause? The mucking about with $^W nukes all the other warnings, save this one.

FWIW, I didn't really get your closing remark " Note that you'll get warnings if File::Spec would do a use warnings." Care to elaborate?