The purpose of this macro was to enable the file-by-file switch to NDO,
after which only tcpdump.c had a use of it and the definitions guarded
by it. Update tcpdump.c not to require them any more and dismiss the
unused definitions.
Have them take a netdissect_options * argument, and get the "no name
resolution" flag from it.
Move the declaration of dnaddr_string to addrtoname.h, along with the
other XXX-to-string routines.
tcpdump used to print an empty line for a Loopback (CTP) packet, which
many Cisco switches send by default every 10 seconds. This commit adds
a decoder for the protocol and a test case, which uses the sample
capture from Wireshark wiki (configuration_test_protocol_aka_loop.pcap).
