Finally...

use lib 'foo';
use Fred;
use Barney;
[download]

is different from

use Fred;
use lib 'foo';
use Barney;
[download]

UPDATE: To clarify, in the former both Fred and Barney are included from foo. In the latter Fred comes from the default location and Barney from foo; assuming copies of Fred and Barney exist in both foo and default locations.

--
perl -wpe "s/\b;([mnst])/'$1/g"