c4bc42419b
On OS X, `netdev2_tap` suspends monitoring file descriptor until `_recv` is called. If no spaces in left in pktbuf, `gnrc_netdev2_eth` does not call `_recv` that results in deadlock. With this commit, `gnrc_netdev2_eth` calls `_recv` with NULL buffer and non-zero length parameter, that indicates the driver to drop frame and resume working.