[BUG] failed to build from source on FreeBSD 15 snapshot

[jiegec]

Describe the bug

From CI log:

https://cirrus-ci.com/task/4917333518450688?logs=build#L41

./Configure -n freebsd
Creating ./lockf_owner.h from /usr/src/sys/kern/kern_lockf.c
./lockf_owner.h creation succeeded.
rm -f ddev.c dfile.c dlsof.h dmnt.c dnode*.c dproc.c dproto.h dsock.c dstore.c dzfs.h kernelbase.h machine.h machine.h.old new_machine.h __lseek.s Makefile Makefile.zfs ./tests/config.cflags
rm -f ./tests/config.cc ./tests/config.xobj ./tests/config.ldflags
Testing C library for localtime() and strftime(), using cc ... present
ln -s lib/dialects/freebsd/dlsof.h dlsof.h
ln -s lib/dialects/freebsd/dmnt.c dmnt.c
ln -s lib/dialects/freebsd/dnode.c dnode.c
ln -s lib/dialects/freebsd/dproc.c dproc.c
ln -s lib/dialects/freebsd/dproto.h dproto.h
ln -s lib/dialects/freebsd/dsock.c dsock.c
ln -s lib/dialects/freebsd/dstore.c dstore.c
ln -s lib/dialects/freebsd/machine.h machine.h
ln -s src/arg.c arg.c
ln -s src/main.c main.c
ln -s src/print.c print.c
ln -s src/ptti.c ptti.c
ln -s src/store.c store.c
ln -s src/usage.c usage.c
ln -s src/util.c util.c
Makefile and lib/Makefile created.
./tests/config.cc created
./tests/config.cflags created
./tests/config.ldflags created
./tests/config.xobj created
WARNING: unsupported dialect or version
make
(cd lib; make DEBUG="-O2" CFGF="-pipe -DNEEDS_BOOL_TYPEDEF -DHASTASKS -DHAS_DUP2 -DHAS_CLOSEFROM -DHASEFFNLINK=i_effnlink -DHASF_VNODE -DHAS_FILEDESCENT -DHAS_TMPFS -DHASWCTYPE_H -DHASSBSTATE -DHAS_KVM_VNODE -DHAS_UFS1_2 -DHAS_VM_MEMATTR_T -DNEEDS_DEVICE_T -DHAS_CDEV2PRIV -DHAS_SYS_SX_H -DHASMSDOSFS -DHAS_V_LOCKF -DHAS_LOCKF_ENTRY -DHAS_NO_6PORT -DHAS_NO_6PPCB -DNEEDS_BOOLEAN_T -DHAS_SB_CCC -DFREEBSDV=15000 -DHASFDESCFS=2 -DHASPROCFS -DHASPSEUDOFS -DHASNULLFS -DHAS9660FS -DHASIPv6 -DHASUTMPX -DHAS_XTCPCB_TMAXSEG -DHAS_KF_SOCK_SENDQ -DHAS_KF_FILE_NLINK -DHAS_STRFTIME -DLSOF_VSTR=\"15.0-CURRENT\"")
cc   -pipe -DNEEDS_BOOL_TYPEDEF -DHASTASKS -DHAS_DUP2 -DHAS_CLOSEFROM -DHASEFFNLINK=i_effnlink -DHASF_VNODE -DHAS_FILEDESCENT -DHAS_TMPFS -DHASWCTYPE_H -DHASSBSTATE -DHAS_KVM_VNODE -DHAS_UFS1_2 -DHAS_VM_MEMATTR_T -DNEEDS_DEVICE_T -DHAS_CDEV2PRIV -DHAS_SYS_SX_H -DHASMSDOSFS -DHAS_V_LOCKF -DHAS_LOCKF_ENTRY -DHAS_NO_6PORT -DHAS_NO_6PPCB -DNEEDS_BOOLEAN_T -DHAS_SB_CCC -DFREEBSDV=15000 -DHASFDESCFS=2 -DHASPROCFS -DHASPSEUDOFS -DHASNULLFS -DHAS9660FS -DHASIPv6 -DHASUTMPX -DHAS_XTCPCB_TMAXSEG -DHAS_KF_SOCK_SENDQ -DHAS_KF_FILE_NLINK -DHAS_STRFTIME -DLSOF_VSTR="15.0-CURRENT" -I/usr/src/sys -I.. -I../include -Idialects/freebsd -O2 -c ckkv.c -o ckkv.o
In file included from ckkv.c:31:
In file included from ./common.h:253:
In file included from ../dlsof.h:171:
In file included from /usr/src/sys/rpc/rpc.h:68:
/usr/src/sys/rpc/svc.h:337:25: error: field has incomplete type 'struct sysctl_ctx_list'
  337 |         struct sysctl_ctx_list sp_sysctl;
      |                                ^
/usr/src/sys/rpc/svc.h:337:9: note: forward declaration of 'struct sysctl_ctx_list'
  337 |         struct sysctl_ctx_list sp_sysctl;
      |                ^
/usr/src/sys/rpc/svc.h:564:12: warning: declaration of 'struct sysctl_oid_list' will not be visible outside of this function [-Wvisibility]
  564 |     struct sysctl_oid_list *sysctl_base);
      |            ^
1 warning and 1 error generated.
*** Error code 1
Stop.
make[1]: stopped making "all" in /tmp/cirrus-ci-build/lib
*** Error code 1
Stop.
make: stopped making "all" in /tmp/cirrus-ci-build

To Reproduce
Steps to reproduce the behavior: see .cirrus.yml.

Expected behavior
It should compile.

Program output

In file included from ckkv.c:31:
In file included from ./common.h:253:
In file included from ../dlsof.h:171:
In file included from /usr/src/sys/rpc/rpc.h:68:
/usr/src/sys/rpc/svc.h:337:25: error: field has incomplete type 'struct sysctl_ctx_list'
  337 |         struct sysctl_ctx_list sp_sysctl;
      |                                ^
/usr/src/sys/rpc/svc.h:337:9: note: forward declaration of 'struct sysctl_ctx_list'
  337 |         struct sysctl_ctx_list sp_sysctl;
      |                ^
/usr/src/sys/rpc/svc.h:564:12: warning: declaration of 'struct sysctl_oid_list' will not be visible outside of this function [-Wvisibility]
  564 |     struct sysctl_oid_list *sysctl_base);
      |            ^
1 warning and 1 error generated.

Environment (please complete the following information):

• Kernel: FreeBSD
• OS: FreeBSD
• lsof Version: git
• Origin: git

Additional context
None