Build fails in libpcap with WITHOUT_INET6

Building r315872 for the Tegra (arm/armv6) board with WITHOUT_INET6 set fails
in libpcap:

> --- klm_prot_xdr.pico ---
> cc -target armv6-gnueabihf-freebsd12.0 --sysroot=/usr/home/randy/tegra/freebs
> d-obj/arm.armv6/usr/home/randy/tegra/freebsd/tmp -B/usr/home/randy/tegra/free
> bsd-obj/arm.armv6/usr/home/randy/tegra/freebsd/tmp/usr/bin -fpic -DPIC -g -O
> -pipe   -DYP -I/usr/home/randy/tegra/freebsd-obj/arm.armv6/usr/home/randy/teg
> ra/freebsd/tmp/usr/include/rpcsvc -MD  -MF.depend.klm_prot_xdr.pico -MTklm_pr
> ot_xdr.pico -std=gnu99 -Wsystem-headers -Werror -Wno-pointer-sign -Wno-empty-
> body -Wno-string-plus-int -Wno-unused-const-variable -Wno-tautological-compar
> e -Wno-unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-
> conversion -Wno-unused-local-typedef -Wno-address-of-packed-member -Wno-switc
> h -Wno-switch-enum -Wno-knr-promoted-parameter -Wno-parentheses  -Qunused-arg
> uments  -c klm_prot_xdr.c -o klm_prot_xdr.pico
> --- all_subdir_lib/libpcap ---
> /usr/home/randy/tegra/freebsd/contrib/libpcap/gencode.c:695:9: error: no memb
> er named 'ai' in 'struct _compiler_state'
>         cstate.ai = NULL;
>         ~~~~~~ ^
> --- all_subdir_lib/librpcsvc ---
> --- mount_xdr.pico ---
> cc -target armv6-gnueabihf-freebsd12.0 --sysroot=/usr/home/randy/tegra/freebs
> d-obj/arm.armv6/usr/home/randy/tegra/freebsd/tmp -B/usr/home/randy/tegra/free
> bsd-obj/arm.armv6/usr/home/randy/tegra/freebsd/tmp/usr/bin -fpic -DPIC -g -O
> -pipe   -DYP -I/usr/home/randy/tegra/freebsd-obj/arm.armv6/usr/home/randy/teg
> ra/freebsd/tmp/usr/include/rpcsvc -MD  -MF.depend.mount_xdr.pico -MTmount_xdr
> .pico -std=gnu99 -Wsystem-headers -Werror -Wno-pointer-sign -Wno-empty-body -
> Wno-string-plus-int -Wno-unused-const-variable -Wno-tautological-compare -Wno
> -unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-conver
> sion -Wno-unused-local-typedef -Wno-address-of-packed-member -Wno-switch -Wno
> -switch-enum -Wno-knr-promoted-parameter -Wno-parentheses  -Qunused-arguments
>   -c mount_xdr.c -o mount_xdr.pico
> --- all_subdir_lib/libpcap ---
> /usr/home/randy/tegra/freebsd/contrib/libpcap/gencode.c:4916:13: error: use o
> f undeclared identifier 'cstate'
>                 bpf_error(cstate, "direction applied to 'gateway'");
>                           ^
> /usr/home/randy/tegra/freebsd/contrib/libpcap/gencode.c:4923:11: error: use o
> f undeclared identifier 'cstate'
>                 switch (cstate->linktype) {
>                         ^
> /usr/home/randy/tegra/freebsd/contrib/libpcap/gencode.c:4961:17: error: use o
> f undeclared identifier 'cstate'
>                 b1 = gen_host(cstate, **alist++, 0xffffffff, proto, Q_OR, Q_H
> OST);
>                               ^
> /usr/home/randy/tegra/freebsd/contrib/libpcap/gencode.c:4963:19: error: use o
> f undeclared identifier 'cstate'
>                         tmp = gen_host(cstate, **alist++, 0xffffffff, proto,
> Q_OR,
>                                        ^
> /usr/home/randy/tegra/freebsd/contrib/libpcap/gencode.c:4972:12: error: use o
> f undeclared identifier 'cstate'
>         bpf_error(cstate, "illegal modifier of 'gateway'");
>                   ^
> 6 errors generated.
> *** [gencode.o] Error code 1
> 
> make[5]: stopped in /usr/home/randy/tegra/freebsd/lib/libpcap
> 1 error
> 
> make[5]: stopped in /usr/home/randy/tegra/freebsd/lib/libpcap
> *** [all_subdir_lib/libpcap] Error code 2