fix so that make unbound-host works when compiled with libnss.
fix so that make unbound-host works when compiled with libnss.

binsys/unbound,LTD-Beget/unbound,LTD-Beget/unbound,binsys/unbound,binsys/unbound,binsys/unbound,LTD-Beget/unbound,LTD-Beget/unbound