HPCC-12693 Fix compile error with old versions of centos

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #6760 from ghalliday/issue12693b

HPCC-12693 Fix compile error with old versions of centos

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>