Update if.h to match Linux kernel headers?

[Szabolcs Nagy]

On 23/06/16 17:06, Florian Weimer wrote:
> On 06/23/2016 05:57 PM, David Miller wrote:
>> From: Florian Weimer <fweimer@redhat.com>
>> Date: Thu, 23 Jun 2016 17:10:54 +0200
>>
>>> On 06/17/2016 11:12 AM, Joseph Myers wrote:
>>>> On Thu, 16 Jun 2016, Carlos O'Donell wrote:
>>>>
>>>>> I'm not entirely sure if userspace can make use of these flags, but
>>>>> one
>>>>> could conceivably write userspace tools and drivers that would.
>>>>
>>>> In <https://sourceware.org/ml/libc-alpha/2014-06/msg00413.html> I
>>>> noted
>>>> that I presumed the exclusion of IFF_* values not fitting in a "short"
>>>> flags field was deliberate.
>>>
>>> Can you elaborate way?  Do you fear that we might end up with an ABI
>>> change if the enum promotes to int, not short?  But doesn't do it that
>>> already, due to the value IFF_DYNAMIC = 0x8000?
>>
>> Because ifr_flags in struct ifreq is 16-bit.
> 
> But these flags are also used for ifr_flags?
> 
> So maybe we should put them into a separate enum block and point to struct ifaddrs and getifaddrs?
> 

i don't see how the enum matters.

and ifr_flags is not the only way to use these
so that should not limit the definitions either.