[PATCH] Factorize net/ethernet.h

[Florian Weimer]

* Samuel Thibault:

> The Linux version is much more up to date, and is OS-independent.
>
> This introduces net/if_ether.h which just pulls linux/if_ether.h, like
> many other such compatibility headers.

Do we want applications to include <net/if_ether.h>?  If not, this
should be a bits/ header, with the usual #error guard.

Thanks,
Florian