HPCC-9819 Fix build break in windows caused by HPCC-9789

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #4722 from ghalliday/issue9819

HPCC-9819 Fix build break in windows caused by HPCC-9789

Merged following review by Jake