thanks AM. This advice has so far solved the /usr/includegd.h mystery, which seems to have been caused by a symlink in /usr to /opt/include (ie where gd.h resides), but has not yet solved the GD.t test failure.

 make test
PERL_DL_NONLAZY=1 /share/MD0_DATA/.qpkg/Optware/bin/perl "-MExtUtils::
+Command::MM" "-e" "test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
t/GD.t ........ Testing using png support.
t/GD.t ........ Failed 11/12 subtests
t/Polyline.t .. ok
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I will try emailing the module director as you suggest