config.h needs to be consistently included before any standard headers
if we ever want to set feature test macros (like _GNU_SOURCE or whatever)
inside. It can lead to hard-to-debug issues without that.
It can also be problematic just for our own HAVE_* that it may define
if it's not consistently made available before our own headers. Just
always include it first, before everything.
We already did this in many files, just not consistently.
Add support for FairPlay SAP v2.5 (encryption type 5) type devices such as Apple Home Pod Minis.
Apparently only these devices require the `POST /feedback` heartbeat, so fix that.
This makes it possible to discover a local RAOP, pulse or RTP services
and connect to them.
IPv6 addresses need the interface appended to local addresses to
make the connection work.
Some AirPlay devices will announce their IPv4 addresses
over IPv6 mDNS if both are available, so the determined
IP version was not reliable.
The prop is not used by module-raop-sink, so its
removal should be safe.
Currently, RAOP sinks referencing the same remote ip and port may be created multiple times:
One each for IPv4 and IPv6, times the number of network interfaces used for mDNS discovery.
A recent change added `(IPv4)`and `(IPv6)`identifiers to the sinks' pretty names, however that
is misleading, as often times the service advertised through an mDNSv6 record is actually an
IPv4 service (i.e. the IP reference contained in the IPv6 record may be an IPv4 address).
With this change, sink creation is skipped if a sink with the same advertised name already exists.
