HPCC-9595 - build fix (for USE_CPPUNIT)

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #5456 from jakesmith/hpcc-9595-cppunit-buildfix

HPCC-9595 - build fix (for USE_CPPUNIT)

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>