tree:   https://kernel.googlesource.com/pub/scm/linux/kernel/git/pablo/nf-next.git master
head:   105333435b4f3b21ffc325f32fae17719310db64
commit: 2a475c409fe81a76fb26a6b023509d648237bbe6 [14/17] kbuild: remove all netfilter headers from header-test blacklist.
config: sparc64-allmodconfig (attached as .config)
compiler: sparc64-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout 2a475c409fe81a76fb26a6b023509d648237bbe6
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=sparc64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from <command-line>:0:0:
>> include/uapi/linux/netfilter_ipv6/ip6t_LOG.h:5:2: warning: #warning "Please update iptables, this file will be removed soon!" [-Wcpp]
    #warning "Please update iptables, this file will be removed soon!"
     ^~~~~~~
--
   In file included from <command-line>:0:0:
>> include/uapi/linux/netfilter_ipv4/ipt_LOG.h:5:2: warning: #warning "Please update iptables, this file will be removed soon!" [-Wcpp]
    #warning "Please update iptables, this file will be removed soon!"
     ^~~~~~~

vim +5 include/uapi/linux/netfilter_ipv6/ip6t_LOG.h

^1da177e4c3f41 include/linux/netfilter_ipv6/ip6t_LOG.h Linus Torvalds     2005-04-16  4  
6939c33a757bd0 include/linux/netfilter_ipv6/ip6t_LOG.h Richard Weinberger 2012-02-10 @5  #warning "Please update iptables, this file will be removed soon!"
6939c33a757bd0 include/linux/netfilter_ipv6/ip6t_LOG.h Richard Weinberger 2012-02-10  6  

:::::: The code at line 5 was first introduced by commit
:::::: 6939c33a757bd006c5e0b8b5fd429fc587a4d0f4 netfilter: merge ipt_LOG and ip6_LOG into xt_LOG

:::::: TO: Richard Weinberger <richard@nod.at>
:::::: CC: Pablo Neira Ayuso <pablo@netfilter.org>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation