extending nss and examples/nss a bit

[tridge at samba.org]

Jerry,

 > What about platforms which don't have NSS and therefore
 > won't build the nss_winbind library ?

that isn't a big problem. The source for our nss_winbind library code
only depends on a very few nss structures and constants, it would not
be difficult to provide a replacement set of structures and defines
for systems that don't have them.

Cheers, Tridge