Refactor fileptr_type_node handling

Refactor fileptr_type_node handling

2017-06-23  Marc Glisse  <marc.glisse@inria.fr>

gcc/
	* tree.h (builtin_structptr_type): New type.
	(builtin_structptr_types): Declare new array.
	* tree.c (builtin_structptr_types): New array.
	(free_lang_data, build_common_tree_nodes): Use it.

gcc/c-family/
	* c-common.c (c_common_nodes_and_builtins): Use builtin_structptr_types.

gcc/cp/
	* decl.c (duplicate_decls): Use builtin_structptr_types.

gcc/lto/
	* lto-lang.c (lto_init): Use builtin_structptr_types.

From-SVN: r249585