fix bug when MPI Master Slave is activated, but without GPUs

src/core/topology.c

@@ -58,7 +58,7 @@ static int nobind;
 /* For checking whether two workers share the same PU, indexed by PU number */
 static int cpu_worker[STARPU_MAXCPUS];
 
-#if defined(STARPU_USE_CUDA) || defined(STARPU_USE_OPENCL) || defined(STARPU_USE_SCC) || defined(STARPU_SIMGRID)
+#if defined(STARPU_USE_CUDA) || defined(STARPU_USE_OPENCL) || defined(STARPU_USE_SCC) || defined(STARPU_SIMGRID) || defined(STARPU_USE_MPI_MASTER_SLAVE)
 
 struct handle_entry
 {