'make buildworld' failure

===> usr.sbin/inetd (all)
cc -target x86_64-unknown-freebsd12.0 --sysroot=/usr/obj/usr/src/tmp -
B/usr/obj/usr/src/tmp/usr/bin  -O2 -pipe -march=nehalem  -DLOGIN_CAP -DIPSEC -
g -MD  -MF.depend.inetd.o -MTinetd.o -std=gnu99 -fstack-protector-strong -
Wsystem-headers -Werror -Wall -Wno-format-y2k -W -Wno-unused-parameter -
Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith -Wno-uninitialized -
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-conversion -Wno-unused-local-typedef  -Qunused-
arguments  -c /usr/src/usr.sbin/inetd/inetd.c -o inetd.o
/usr/src/usr.sbin/inetd/inetd.c:319:28: error: implicit declaration of 
function 'satosin6' is
      invalid in C99 [-Werror,-Wimplicit-function-declaration]
            IN6_IS_ADDR_V4MAPPED(&satosin6(sa)->sin6_addr))
                                  ^
/usr/src/usr.sbin/inetd/inetd.c:319:42: error: member reference type 'int' is 
not a pointer
            IN6_IS_ADDR_V4MAPPED(&satosin6(sa)->sin6_addr))
                                  ~~~~~~~~~~~~  ^
/usr/obj/usr/src/tmp/usr/include/netinet6/in6.h:266:4: note: expanded from 
macro
      'IN6_IS_ADDR_V4MAPPED'
        ((a)->__u6_addr.__u6_addr32[0] == 0 &&  \
          ^
/usr/src/usr.sbin/inetd/inetd.c:319:42: error: member reference type 'int' is 
not a pointer
            IN6_IS_ADDR_V4MAPPED(&satosin6(sa)->sin6_addr))
                                  ~~~~~~~~~~~~  ^
/usr/obj/usr/src/tmp/usr/include/netinet6/in6.h:267:4: note: expanded from 
macro
      'IN6_IS_ADDR_V4MAPPED'
         (a)->__u6_addr.__u6_addr32[1] == 0 &&  \
          ^
/usr/src/usr.sbin/inetd/inetd.c:319:42: error: member reference type 'int' is 
not a pointer
            IN6_IS_ADDR_V4MAPPED(&satosin6(sa)->sin6_addr))
                                  ~~~~~~~~~~~~  ^
/usr/obj/usr/src/tmp/usr/include/netinet6/in6.h:268:4: note: expanded from 
macro
      'IN6_IS_ADDR_V4MAPPED'
         (a)->__u6_addr.__u6_addr32[2] == ntohl(0x0000ffff))
          ^
4 errors generated.
*** Error code 1



root_at_asus:/usr/src # svnlite info|grep Rev:
Last Changed Rev: 311250

My current system revision is r310560

 It possible that it is due to WITHOUT_INET6 defined in /etc/src.conf