Thank you. This is outside my expertise, so I appreciate the detailed response. Your patch seems to work, though I haven't run it against the test suite. I've also added a parallel line for STDERR, replacing

            xclose $dad_err;
            xopen \*STDERR, ">&=" . fileno $kid_err;
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with

            xclose $dad_err;
            open STDERR, ">&=2";
            xopen \*STDERR, ">&=" . fileno $kid_err;
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which seems to behave for STDERR redirects. Now I have the moral quandry of using local modules, or using the distributed version with a work around.