HPCC-12139 Spurious Warnings concerning -L libaprlib.dylib on OSX

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #6385 from richardkchapman/apr-library-paths

HPCC-12139 Spurious Warnings concerning -L libaprlib.dylib on OSX

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>