Maybe the Test Harness is cocking up my STDOUT file descriptor?

I've never managed to understand anything about problems that arise only when Test::Harness is invoked.
(Best news would have been for you to report "Nope - makes no difference" ;-)

perl "-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef *Test::Harness::Switches; test_harness(0, 'blib\lib', 'blib\arch')" t\00-report-prereqs.t

A shot in the dark - does it make any difference if you remove undef *Test::Harness::Switches; from that command ?

You mention another build of perl on another system where this problem does not arise.
Do both systems run the same command when 'make test' is run ? (Obviously, they'll invoke different perls.)
Do both systems run the same version of Test::Harness: 
perl -MTest::Harness -e "print $Test::Harness::VERSION"

[download]

Cheers,
Rob

In reply to Re^3: Bad file descriptor error in Win32 VC2015 compiled perl-5.20.3 by syphilis
in thread Bad file descriptor error in Win32 VC2015 compiled perl-5.20.3 by shadowsong

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