cannot build XEN kernel on amd64 machine

lissyara# uname -a
FreeBSD lissyara.moskb.local 8.0-CURRENT FreeBSD 8.0-CURRENT #0: Tue Nov 
18 18:24:01 MSK 2008     
lissyara_at_lissyara.moskb.local:/usr/obj/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/GENERIC  
amd64
lissyara# make buildkernel KERNCONF=XEN TARGET_ARCH=i386

......... skipped .........

--------------------------------------------------------------
 >>> stage 3.1: making dependencies
--------------------------------------------------------------
cd /usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/XEN; 
MAKEOBJDIRPREFIX=/usr/obj/i386  MACHINE_ARCH=i386  MACHINE=i386  
CPUTYPE=  
GROFF_BIN_PATH=/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp/legacy/usr/bin  
GROFF_FONT_PATH=/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp/legacy/usr/share/groff_font  
GROFF_TMAC_PATH=/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp/legacy/usr/share/tmac  
_SHLIBDIRPREFIX=/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp  
VERSION="FreeBSD 8.0-CURRENT amd64 800053"  INSTALL="sh 
/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tools/install.sh"  
PATH=/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp/legacy/usr/sbin:/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp/legacy/usr/bin:/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp/legacy/usr/games:/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp/usr/sbin:/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp/usr/bin:/usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/tmp/usr/games:/sbin:/bin:/usr/sbin:/usr/bin 
NO_CTF=1 make KERNEL=kernel depend -DNO_MODULES_OBJ
machine -> /mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/i386/include
cc -c -O -pipe -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/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/contrib/altq 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/contrib/ipfilter 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/contrib/pf 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/dev/ath 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/contrib/ngatm 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/dev/twa 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/gnu/fs/xfs/FreeBSD 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/gnu/fs/xfs/FreeBSD/support 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/gnu/fs/xfs 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/contrib/opensolaris/compat 
-I/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/dev/cxgb -D_KERNEL 
-DHAVE_KERNEL_OPTION_HEADERS -include opt_global.h -finline-limit=8000 
--param inline-unit-growth=100 --param large-function-growth=1000 
-mno-align-long-strings -mpreferred-stack-boundary=2 -mno-mmx -mno-3dnow 
-mno-sse -mno-sse2 -mno-sse3 -ffreestanding -fstack-protector 
/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/i386/i386/genassym.c
/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/i386/i386/genassym.c:1: error: 
-mpreferred-stack-boundary=2 is not between 4 and 12
*** Error code 1

Stop in /usr/obj/i386/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/XEN.
*** Error code 1

Stop in /mnt/jabber/DISTR/FreeBSD/src/CURRENT.
*** Error code 1

Stop in /mnt/jabber/DISTR/FreeBSD/src/CURRENT.
lissyara#