Error in buildkernel

From: Filippo Moretti via current <current_at_freebsd.org>
Date: Thu, 29 Jul 2021 07:16:04 UTC
Good morning,                        I have the following error in build kernel:ror=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 -Werror vers.c
ctfconvert -L VERSION -g vers.o
linking kernel.full
ld: error: undefined symbol: xen_clock_init
>>> referenced by pv.c
>>>               pv.o:(xen_pvh_init_ops)

ld: error: undefined symbol: xen_delay
>>> referenced by pv.c
>>>               pv.o:(xen_pvh_init_ops)
*** Error code 1

Stop.
make[2]: stopped in /usr/obj/usr/src/amd64.amd64/sys/STING
*** Error code 1

Stop.
make[1]: stopped in /usr/src

[root@sting /usr/src]# uname -a
FreeBSD sting 14.0-CURRENT FreeBSD 14.0-CURRENT #43 main-n248147-8539518055d: Thu Jul 22 11:36:29 CEST 2021     root@sting:/usr/obj/usr/src/amd64.amd64/sys/STING  amd64

sincerelyFilippo