Allow linking with multiple device drivers.

Apart from the platform specific tun/tap driver, link with the dummy and
raw_socket devices, and optionally with support for UML and VDE devices.
At runtime, the DeviceType option can be used to select which driver to
use.

src/tincd.c

@@ -650,7 +650,7 @@ int main2(int argc, char **argv) {
 	/* Shutdown properly. */
 
 	ifdebug(CONNECTIONS)
-		dump_device_stats();
+		devops.dump_stats();
 
 	close_network_connections();