simplify the tree structure building by removing topology_dup altogether

src/core/workers.c

@@ -1043,18 +1043,14 @@ static void _starpu_build_tree(void)
 	struct starpu_tree *tree;
 	_STARPU_MALLOC(tree, sizeof(struct starpu_tree));
 	_starpu_config.topology.tree = tree;
-#if HWLOC_API_VERSION >= 0x00010800
-	hwloc_topology_dup(&cpu_topo, _starpu_config.topology.hwtopology);
-#else
-	hwloc_topology_init(&cpu_topo);
-	hwloc_topology_load(cpu_topo);
-#endif
 
+	hwloc_topology_init(&cpu_topo);
 #if HWLOC_API_VERSION >= 0x20000
 	hwloc_topology_set_all_types_filter(cpu_topo, HWLOC_TYPE_FILTER_KEEP_STRUCTURE);
 #else
 	hwloc_topology_ignore_all_keep_structure(cpu_topo);
 #endif
+	hwloc_topology_load(cpu_topo);
 	hwloc_obj_t root = hwloc_get_root_obj(cpu_topo);
 
 /* 	char string[128]; */