HPCC-9956 Fix build break in windows introduced by previous commit.

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #4904 from ghalliday/issue9956b

HPCC-9956 Fix build break in windows introduced by previous commit.

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>