widl: Add a --local-stubs option.

[Robert Shearman]

Dan Hipschman wrote:
> +        write_type_decl_left(fp, mdef->type);
> +        fprintf(fp, " CALLBACK %s_", iface->name);
> +        write_name(fp, mdef);
> +        fprintf(fp, "_Proxy(\n");
> +        write_args(fp, m->args, iface->name, 1, TRUE);
> +        fprintf(fp, ")");
> +        if (body) {
> +          type_t *rt = mdef->type;
> +          fprintf(fp, "\n{\n");
> +          fprintf(fp, "    %s\n", comment);
> +          if (rt->name && strcmp(rt->name, "HRESULT") == 0)
> +            fprintf(fp, "    return E_FAIL;\n");
>
>   

It would be better to make the default implementation of the stubs 
return E_NOTIMPL instead of E_FAIL, since the former is a lot more 
specific and makes identifying the source of misbehaviour of an 
application easier.

-- 
Rob Shearman