Fix TYPE_DECLARED_CLASS thinko

Fix TYPE_DECLARED_CLASS thinko

Simon pointed out an error that I made in
compile_cplus_conver_struct_or_union in my original C++ compile submission:

  if (type->code () == TYPE_CODE_STRUCT)
    {
      const char *what = TYPE_DECLARED_CLASS (type) ? "struct" : "class";

      resuld = instance->plugin ().build_decl
        (what, name.get (), (GCC_CP_SYMBOL_CLASS | nested_access
                             | (TYPE_DECLARED_CLASS (type)
                                ? GCC_CP_FLAG_CLASS_NOFLAG
                                : GCC_CP_FLAG_CLASS_IS_STRUCT)),
         0, nullptr, 0, filename, line);
    }

Notice that WHAT will contain "struct" for TYPE_DECLARED_CLASS. Whoops.

Fortunately this first parameter of build_decl is only used for
debugging.

gdb/ChangeLog
2021-03-24  Keith Seitz  <keiths@redhat.com>

	* compile/compile-cplus-types.c
	(compile_cplus_convert_struct_or_union): Fix TYPE_DECLARED_CLASS
	thinko.