examples/stencil/stencil-blocks.c: add missing variable

examples/stencil/stencil-blocks.c

@@ -300,6 +300,7 @@ void allocate_memory_on_node(int rank)
 		/* Main blocks */
 		if (node == rank)
 		{
+			unsigned size_bz = block_sizes_z[bz];
 			allocate_block_on_node(&block->layers_handle[0], bz, &block->layers[0],
 						(sizex + 2*K), (sizey + 2*K), (size_bz + 2*K));
 #ifndef STARPU_SIMGRID