localhost not preloaded

[daurnimator]

I was suprised to see dns.c reach out to my dns server to ask about 'localhost'.

rfc6761:

6.3. Domain Name Reservation Considerations for "localhost."

...

3. Name resolution APIs and libraries SHOULD recognize localhost
   names as special and SHOULD always return the IP loopback address
   for address queries and negative responses for all other query
   types. Name resolution APIs SHOULD NOT send queries for
   localhost names to their configured caching DNS server(s).

I tracked this down to be due to /etc/hosts not containing a 'localhost' entry: dns.c needs to treat localhost specially.