Re: [PATCH 2/4] netlink: Fix compilation on really old platforms

Hi Marcel,

>> -linux_headers = linux/gpio.h
>> +linux_headers = linux/gpio.h linux/netlink.h
> 
> so while we could do this, I really don’t like it. Running after upstream netlink.h changes is something I rather not keep doing. For the nl80211.h header this is semi-ok, but I rather not keep doing that for all netlink headers.

We don't really need to run after them, the EXT_ACK support has been in there fr 
some time.  The problem is that EXT_ACK uses a ton of other attributes missing 
from linux-headers circa 2016.  The missing #defines are easy enough to add to 
missing.h, but the problem is this one:

+enum nlmsgerr_attrs {
+       NLMSGERR_ATTR_UNUSED,
+       NLMSGERR_ATTR_MSG,
+       NLMSGERR_ATTR_OFFS,
+       NLMSGERR_ATTR_COOKIE,
+       NLMSGERR_ATTR_POLICY,
+       NLMSGERR_ATTR_MISS_TYPE,
+       NLMSGERR_ATTR_MISS_NEST,
+
+       __NLMSGERR_ATTR_MAX,
+       NLMSGERR_ATTR_MAX = __NLMSGERR_ATTR_MAX - 1
+};

That is an enumeration.  Maybe we could write a configure-time test for this, 
but that's a pain...

Same situation with rtnetlink.h, RTA_EXPIRES is an enum, so a configure-time 
test is required.

Regards,
-Denis