go-gcc.cc (set_placeholder_pointer_type): Arrange for the type name to have a DECL_ORIGINAL_TYPE as gcc expects.

	* go-gcc.cc (set_placeholder_pointer_type): Arrange for the type
	name to have a DECL_ORIGINAL_TYPE as gcc expects.
	(set_placeholder_struct_type): Likewise.
	(set_placeholder_array_type): Likewise.
	(named_type): Set DECL_ORIGINAL_TYPE.

From-SVN: r182639