- only include openssl if the openssl option is present
- include arpa/inet.h to get ntohl and friends on older platforms like
Interix
- use new netdb.h compat code from libnbcompat
- include inttypes.h only when present
- don't name local variables err, Interix has a symbol like that in
default namespace
- allow fetch_read to do short read and do more intelligent buffering
for header processing; effectively don't do a system call for each
byte read
