HPCC-9229 Fix build break on more modern compilers

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #4347 from ghalliday/issue9229

HPCC-9229 Fix build break on more modern compilers

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>