package GLOBAL
use 'Exporter';
@ISA = qw(Exporter); #not always needed, but usually a good practice
@EXPORT = qw(compress);
...

1;

package MODULE

use GLOBAL;
use Exporter;
@ISA = qw(Exporter); #again, usually a good practice.
@EXPORT = qw(test);

sub test {
compress "test\n";
}

1;