vnode_if.h not found / make buildkernel on FreeBSD/HEAD-16

Hello,

When building a kernel for -CURRENT, with fresh source from today at
2574974648c68c738aec3ff96644d888d7913a37, it fails with this error:

cc -target x86_64-unknown-freebsd16.0 --sysroot=/usr/obj/usr/src/amd64.amd64/tmp -B/usr/obj/usr/src/amd64.amd64/tmp/usr/bin -c -O2 -pipe -fno-strict-aliasing -g -nostdinc -I. -I/usr/src/sys -I/usr/src/sys/contrib/ck/include -I/usr/src/sys/contrib/libfdt -D_KERNEL -DHAVE_KERNEL_OPTION_HEADERS -include opt_global.h -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -MD -MF.depend.genassym.o -MTgenassym.o -fdebug-prefix-map=./machine=/usr/src/sys/amd64/include -fdebug-prefix-map=./x86=/usr/src/sys/x86/include -fdebug-prefix-map=./i386=/usr/src/sys/i386/include -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float -fno-asynchronous-unwind-tables -ffreestanding -fwrapv -fstack-protector -gdwarf-4 -Wall -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 -Wswitch -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=gnu17  -fcommon /usr/src/sys/amd64/amd64/genassym.c
In file included from /usr/src/sys/amd64/amd64/genassym.c:49:
In file included from /usr/src/sys/sys/mount.h:965:
/usr/src/sys/sys/vnode.h:612:10: fatal error: 'vnode_if.h' file not found
  612 | #include "vnode_if.h"
      |          ^~~~~~~~~~~~
1 error generated.
*** Error code 1

Stop.
make[2]: stopped making "all" in /usr/obj/usr/src/amd64.amd64/sys/GENERIC
        1,00 real         0,86 user         0,15 sys

Note: the same error was reported 3 days ago on the forums:
https://forums.freebsd.org/threads/vnode_if-h-not-found-make-buildkernel-on-freebsd-head-16.102681/

Any ideas?
-- 
Th. Thomas.