compilation failure

error: reference to 'mutex' is ambiguous
note: candidates are: 'class boost::mutex'
note:                 'class std::mutex'

dbcon/joblist/tupleaggregatestep.cpp

@@ -414,7 +414,7 @@ void TupleAggregateStep::initializeMultiThread()
 
     for (i = 0; i < fNumOfBuckets; i++)
     {
-        mutex* lock = new mutex();
+		boost::mutex* lock = new boost::mutex();
         fAgg_mutex.push_back(lock);
         fRowGroupOuts[i] = fRowGroupOut;
         rgData.reinit(fRowGroupOut);