Declare signal_reopen_log_files as a sig_atomic_t

Strictly aligning to POSIX, signal_reopen_log_files must be a volatile sig_atomic_t.

«the behavior is undefined if the signal handler refers to any object other than errno with static storage duration other than by assigning a value to an object declared as volatile sig_atomic_t, or [calls a non-async-signal-safe function]»
https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04_03_03

Add support for loopback/null devices

Added flag for Resource Record Type

avoid segfault on non-ethernet links

eg. `-i any`, which has link-type LINUX_SLL (Linux cooked v1)

log hardware addresses of involved parties

Speed up the search (removed the explicit like %term)

add quiet mode option

Fix linux DLT_LINUX_SLL ifdef.

Implement support of YMDHMS timestamp format in JSON output.

minor autoconf changes to port to openbsd

Print stats to specified file (-s <file>) instead of STDOUT on
signal (SIGUSR1).

-N option to set interface(pcap_open_live) to non promisc. mode

update passet->af in update_pdns_record_asset/get_pdns_record

Newer versions of ldns requires OpenSSL to compile. Therefore,
OpenSSL is now added as a dependency when running configure.

Added automake to OS X dependencies

Changed the logic implemented to reopen log files when a HUP signal
is sent to avoid occasional deadlocks.

Old Debian versions use a LDNS version that does not have
NSEC3PARAM. Disable NSEC3PARAM if it is not defined, to
make passivedns work with slightly older LDNS versions.

Fixed redifinition warning (automake)