ip_divert.c:374:7: error: use of undeclared identifier

FYI

FreeBSD Free_BSD_13 13.0-CURRENT FreeBSD 13.0-CURRENT #22 r356360: Sat Jan 
4 20:10:21 EST 2020 
root_at_Free_BSD_13:/usr/obj/usr/src/amd64.amd64/sys/MYKERNEL  amd64 1300074


--- all_subdir_dtrace ---
--- prototype.o ---
cc -target x86_64-unknown-freebsd13.0 
--sysroot=/usr/obj/usr/src/amd64.amd64/tmp 
-B/usr/obj/usr/src/amd64.amd64/tmp/usr/bin  -O2 -pipe 
-fno-strict-aliasing -Werror -D_KERNEL -DKLD_MODULE -DKLD_TIED -nostdinc 
-I/usr/src/sys/cddl/compat/opensolaris 
-I/usr/src/sys/cddl/contrib/opensolaris/uts/common -I/usr/src/sys 
-DHAVE_KERNEL_OPTION_HEADERS -include 
/usr/obj/usr/src/amd64.amd64/sys/MYKERNEL/opt_global.h -I. -I/usr/src/sys 
-I/usr/src/sys/contrib/ck/include -fno-common -g -fno-omit-frame-pointer 
-mno-omit-leaf-frame-pointer 
-fdebug-prefix-map=./machine=/usr/src/sys/amd64/include 
-fdebug-prefix-map=./x86=/usr/src/sys/x86/include 
-I/usr/obj/usr/src/amd64.amd64/sys/MYKERNEL     -MD 
-MF.depend.prototype.o -MTprototype.o -mcmodel=kernel -mno-red-zone 
-mno-mmx -mno-sse -msoft-float  -fno-asynchronous-unwind-tables 
-ffreestanding -fwrapv -fstack-protector -gdwarf-2 -Wall -Wredundant-decls 
-Wnested-externs -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith 
-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 
-Wno-address-of-packed-member -Wno-format-zero-length   -mno-aes -mno-avx 
-std=iso9899:1999 -include 
/usr/src/sys/cddl/compat/opensolaris/sys/debug_compat.h -c 
/usr/src/sys/cddl/dev/prototype.c -o prototype.o
--- all_subdir_iir ---
--- iir.ko.debug ---
objcopy --only-keep-debug iir.ko.full iir.ko.debug
--- iir.ko ---
objcopy --strip-debug --add-gnu-debuglink=iir.ko.debug  iir.ko.full iir.ko
--- all_subdir_ipdivert ---
/usr/src/sys/netinet/ip_divert.c:374:7: error: use of undeclared 
identifier 'IPV6_VERSION'
         case IPV6_VERSION >> 4:
              ^
--- all_subdir_ipfilter ---
===> ipfilter (all)
[Creating objdir 
/usr/obj/usr/src/amd64.amd64/sys/MYKERNEL/modules/usr/src/sys/modules/ipfilter...]
--- all_subdir_ipdivert ---
1 error generated.
*** [ip_divert.o] Error code 1

make[4]: stopped in /usr/src/sys/modules/ipdivert
1 error

make[4]: stopped in /usr/src/sys/modules/ipdivert
*** [all_subdir_ipdivert] Error code 2