include/resolv.h: provide __res_state._u even if !__UCLIBC_HAS_IPV6__
include/resolv.h: provide __res_state._u even if !__UCLIBC_HAS_IPV6__

This struct is used for IPv4 as well, so only make the members
conditional that are purely used by IPv6.

Signed-off-by: Daniel Mack <70806a71956ed8873ecff8522779dae1401a1b4a@gmail.com>

ffainelli/uClibc,ffainelli/uClibc,majek/uclibc-vx32,brgl/uclibc-ng,atgreen/uClibc-moxie,mephi42/uClibc,hwoarang/uClibc,ndmsystems/uClibc,majek/uclibc-vx32,majek/uclibc-vx32,kraj/uclibc-ng,wbx-github/uclibc-ng,kraj/uClibc,ddcc/klee-uclibc-0.9.33.2,ndmsystems/uClibc,waweber/uclibc-clang,wbx-github/uclibc-ng,foss-for-synopsys-dwc-arc-processors/uClibc,waweber/uclibc-clang,hwoarang/uClibc,kraj/uClibc,waweber/uclibc-clang,czankel/xtensa-uclibc,ffainelli/uClibc,hwoarang/uClibc,foss-xtensa/uClibc,foss-for-synopsys-dwc-arc-processors/uClibc,hjl-tools/uClibc,skristiansson/uClibc-or1k,majek/uclibc-vx32,foss-for-synopsys-dwc-arc-processors/uClibc,ddcc/klee-uclibc-0.9.33.2,kraj/uClibc,hjl-tools/uClibc,hjl-tools/uClibc,wbx-github/uclibc-ng,hwoarang/uClibc,groundwater/uClibc,groundwater/uClibc,groundwater/uClibc,brgl/uclibc-ng,groundwater/uClibc,foss-xtensa/uClibc,foss-for-synopsys-dwc-arc-processors/uClibc,atgreen/uClibc-moxie,atgreen/uClibc-moxie,ndmsystems/uClibc,wbx-github/uclibc-ng,skristiansson/uClibc-or1k,mephi42/uClibc,skristiansson/uClibc-or1k,ddcc/klee-uclibc-0.9.33.2,ddcc/klee-uclibc-0.9.33.2,ffainelli/uClibc,mephi42/uClibc,kraj/uclibc-ng,mephi42/uClibc,kraj/uclibc-ng,atgreen/uClibc-moxie,groundwater/uClibc,skristiansson/uClibc-or1k,czankel/xtensa-uclibc,czankel/xtensa-uclibc,czankel/xtensa-uclibc,waweber/uclibc-clang,ndmsystems/uClibc,hjl-tools/uClibc,hjl-tools/uClibc,brgl/uclibc-ng,kraj/uClibc,foss-xtensa/uClibc,foss-xtensa/uClibc,brgl/uclibc-ng,kraj/uclibc-ng,ffainelli/uClibc