r292688: ix_txrx.c:812:4: error: use of undeclared identifier 'ip6';

Building kernel on r292688 fails with the error shown below:

[...]
cc  -O2 -pipe -O3 -O3 -pipe -march=native  -fno-strict-aliasing -Werror -D_KERNEL
-DKLD_MODULE -nostdinc   -DHAVE_KERNEL_OPTION_HEADERS
-include /usr/obj/usr/src/sys/GATE/opt_global.h -I. -I/usr/src/sys -fno-common
-fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -I/usr/obj/usr/src/sys/GATE
-mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float
-fno-asynchronous-unwind-tables -ffreestanding -fwrapv -fstack-protector -Wall
-Wredundant-decls -Wnested-externs -Wstrict-prototypes  -Wmissing-prototypes
-Wpointer-arith -Winline -Wcast-qual  -Wundef -Wno-pointer-sign
-D__printf__=__freebsd_kprintf__  -Wmissing-include-dirs -fdiagnostics-show-option
-Wno-unknown-pragmas  -Wno-error-tautological-compare -Wno-error-empty-body
-Wno-error-parentheses-equality -Wno-error-unused-function  -Wno-error-pointer-sign
-Wno-error-shift-negative-value  -mno-aes -mno-avx  -std=iso9899:1999
-c /usr/src/sys/modules/isci/../../dev/isci/scil/scif_sas_smp_remote_device.c -o
scif_sas_smp_remote_device.o --- all_subdir_iwnfw --- --- iwn5150fw.ko --- ld -d
-warn-common -r -d -o iwn5150fw.ko iwlwifi-5150-8.24.2.2.fw.fwo iwn5150fw.o :>
export_syms awk -f /usr/src/sys/conf/kmod_syms.awk iwn5150fw.ko  export_syms | xargs -J%
objcopy % iwn5150fw.ko --- all_subdir_ix --- --- ix_txrx.o
--- /usr/src/sys/modules/ix/../../dev/ixgbe/ix_txrx.c:812:4: error: use of undeclared
identifier 'ip6'; did you mean 'ip'? ip6 = (struct ip6_hdr *)(l3d); ^~~
ip /usr/src/sys/modules/ix/../../dev/ixgbe/ix_txrx.c:730:13: note: 'ip' declared here
struct ip *ip; ^ /usr/src/sys/modules/ix/../../dev/ixgbe/ix_txrx.c:812:8: error:
incompatible pointer types assigning to 'struct ip *' from 'struct ip6_hdr
*' [-Werror,-Wincompatible-pointer-types] ip6 = (struct ip6_hdr *)(l3d); ^
~~~~~~~~~~~~~~~~~~~~~~~ /usr/src/sys/modules/ix/../../dev/ixgbe/ix_txrx.c:814:14: error:
use of undeclared identifier 'ip6' ipproto = ip6->ip6_nxt; ^ --- all_subdir_isci ---