Adding changes required to compile and run Jool on Vyos

[ecazarez]

The kernel version used by VyOS has a problem with duplicated header files, with different content in the different versions of some files. This has as consequence that it not possible to compile Jool on VyOS.

The included changes solve the problem of the files with reduced functionality using explicitly the right ones. This enables the compilation of Jool on VyOS, and now it is possible to run it on VyOS.

[ydahhrk]

Sorry for taking so long.

I think there might be a bug hidden in this solution somewhere: From what I can tell, the changes apply to kernel 4.5. However, in the test VyOS virtual machine I'm testing on the official running kernel is 3.13. (VyOS itself is 1.1.8.)

How did you download the kernel headers?

Also, I have a nitpick: There's significant code duplication going on in this commit. Could you please put the changes in a file called something like include/nat64/mod/common/vyos-compatibility.h and just #include that from all the affected files? (I don't mind doing this myself if you don't have the time.)

[frebib]

This can probably be closed. Vyos managed to package Jool successfully in https://github.com/vyos/vyos-build/commit/d9f711f500ea21288a50f54640dff833cd1da153