can't compile debug kernel

Hello

I try to create a debug kernel with freebsd current 64bit. I added all  
options described in http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug-deadlocks.html 
:

makeoptions     DEBUG=-g
options         INVARIANTS
options         INVARIANT_SUPPORT
options         WITNESS
options         DEBUG_LOCKS
options         DEBUG_VFS_LOCKS
options         DIAGNOSTIC
options         KDB
options         KDB

I always get:  /usr/src/sys/kern/kern_lock.c:917: undefined reference  
to `stack_print_ddb'

cc -c -O2 -frename-registers -pipe -fno-strict-aliasing  -std=c99 -g - 
Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes  -Wmissing- 
prototypes -Wpointer-arith -Winline -Wcast-qual  -Wundef -Wno-pointer- 
sign -fformat-extensions -nostdinc  -I. -I/usr/src/sys -I/usr/src/sys/ 
contrib/altq -D_KERNEL -DHAVE_KERNEL_OPTION_HEADERS -include  
opt_global.h -fno-common -finline-limit=8000 --param inline-unit- 
growth=100 --param large-function-growth=1000  -fno-omit-frame-pointer  
-mcmodel=kernel -mno-red-zone  -mfpmath=387 -mno-sse -mno-sse2 -mno- 
sse3 -mno-mmx -mno-3dnow  -msoft-float -fno-asynchronous-unwind-tables  
-ffreestanding -fstack-protector -Werror  vers.c
linking kernel.debug
kern_lock.o(.text+0x245): In function `lockmgr_printinfo':
/usr/src/sys/kern/kern_lock.c:917: undefined reference to  
`stack_print_ddb'
*** Error code 1

Would anyone care to tell me what i'm doing wrong?

Regards,
Thomas