lock with openoffice build with libkse

[Martin Blapp]

Hi,

> -	return (pthread_sigmask(how, set, oset));
> +	if (_kse_isthreaded() != 0)
> +		return (pthread_sigmask(how, set, oset));
> +	else
> +		return (__sys_sigprocmask(how, set, oset));
>  }

This fixes the build problem. Thank you !

Martin