Fix buildbreak for missing error code from cstdlib

Change-Id: I6b15a0d0169161f24a81a571ceb6dabfacc87eb2
Reviewed-on: http://review.couchbase.org/23983
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>