* class.c (struct vtbl_init_data_s): Remove last_init field.
(struct secondary_vptr_vtt_init_data_s): Change type of inits field
to a VEC.
(finish_vtbls): Use a VEC rather than a TREE_LIST for the accumulated
initializers.
(build_vtt): Likewise.
(initialize_vtable): Take a VEC instead of a tree.
(build_vtt_inits): Change return type to void. Take a VEC **
instead of a tree *; accumulate results into said VEC.
(build_ctor_vtbl_group): Use a VEC rather than a TREE_LIST for the
accumulated initializers. Pass the vtable to accumulate_vtbl_inits.
(accumulate_vtbl_inits): Add extra vtable tree parameter; take a VEC
instead of a tree.
(dfs_accumulate_vtbl_inits): Likewise. Change return type to void.
(build_vtbl_initializer): Add VEC parameter; accumulate initializers
into it.
(dfs_build_secondary_vptr_vtt_inits): Use CONSTRUCTOR_APPEND_ELT
rather than tree_cons.
(build_vbase_offset_vtbl_entries): Likewise.
(add_vcall_offset): Likewise.
(build_rtti_vtbl_entries): Likewise.
* cp-tree.h (initialize_artificial_var): Take a VEC instead of a tree.
* decl.c (initialize_artificial_var): Use build_constructor instead
of build_constructor_from_list.