As the compile may or may not link to GMP, using projects
need to link to this too. Dynamic libs handle this, we ship
static libs and thus we need to handle this ourselves.
For service applications that bind to networks (currently
only indexer) this allows users to pass the address:
0.0.0.0
to bind to. The effect will be that we find all the network
interfaces in the system and bind to all of them.
Notice that we already had "localhost" as an alias to bind to both
v4 and v6 loopback interfaces.
This new feature depends on optional dependency QtNetwork.
TomZ