[krbdev.mit.edu #2710] use BIND 8 parsing API

[kenh@cmf.nrl.navy.mil via RT]

>We should be using the BIND 8 parsing API (ns_initparse, etc.) rather
>than relying on the HEADER struct (which I think is BIND 4). 
>Apparently, using -DBIND_8_COMPAT to make the HEADER struct visible can
>turn off the res_nsearch() prototype, etc.  If we use the ns_* API on
>BIND 8 and 9, we can stop using -DBIND_8_COMPAT.

It seems to me that at least under MacOS X 10.3.5 and Solaris 8, the
ns_initparse() API isn't prototyped in resolv.conf.

--Ken