net/ethernet.h and linux/if_tunnel.h do not appear to be needed
on lib/netdev-linux.c.
I noticed this while trying to build on the Android NDK r6b (Android API
level 13) as these headers are not present there.
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <netpacket/packet.h>
-#include <net/ethernet.h>
#include <net/if.h>
-#include <linux/if_tunnel.h>
#include <net/if_arp.h>
#include <net/if_packet.h>
#include <net/route.h>