HPCC-11281 Fix OSX compile issues with file caching

Update for OSX which does not have SYNC_FILE_RANGE constants

Signed-off-by: Mark Kelly <mark.kelly@lexisnexis.com>
Merge pull request #5766 from mckellyln/hpcc11281

HPCC-11281 Fix OSX compile issues with file caching

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>