Thomas Haller authored Dec 11, 2017 and Lubomir Rintel committed Dec 11, 2017

We're going to need that one for TC filter & action support.

<linux/tc_act/tc_defact.h> was moved to user-space API only in 2013
by commit 5bc3db5c9ca8407f52918b6504d3b27230defedc. Our travis CI currently
fails to build due to that.

Re-implement the header.