How to build kernel modules for xen?

Xen kernel is built with DEBUG and DIAGNOSTIC and the kernel modules are 
not so they conflict.

So I want to build modules with those options. But I don't see any 
build.sh config for building just modules. It was suggested that I build 
my modules for xen and not i386 because of different headers.

So I am attempting to build all with:

   time ./build.sh -U -m xen -a i386 build 

But then fails with:

dependall ===> lib/csu/i386_elf
#    create  i386_elf/crt0.d
CC=/usr/src/netbsd-3/src/tooldir.NetBSD-3.99.21-i386/bin/i386--netbsdelf-gcc 
/usr/src/netbsd-3/src/tooldir.NetBSD-3.99.21-i386/bin/nbmkdep -f crt0.d --      
-I- -I/usr/src/netbsd-3/src/lib/csu/i386_elf -DLIBC_SCCS -DPIC -DDYNAMIC 
-DELFSIZE=32 -I/usr/src/netbsd-3/src/libexec/ld.elf_so 
-I/usr/src/netbsd-3/src/lib/csu/i386_elf/../common_elf 
-I/usr/src/netbsd-3/src/lib/libc/dlfcn -DDWARF2_EH -DJCR -DDSO_HANDLE  
-nostdinc -isystem /usr/src/netbsd-3/src/destdir.xen/usr/include   
/usr/src/netbsd-3/src/lib/csu/i386_elf/crt0.c
In file included from 
/usr/src/netbsd-3/src/lib/csu/common_elf/common.h:37,
                 from /usr/src/netbsd-3/src/lib/csu/i386_elf/crt0.c:38:
/usr/src/netbsd-3/src/destdir.xen/usr/include/sys/types.h:45:27: 
machine/types.h: No such file or directory
/usr/src/netbsd-3/src/destdir.xen/usr/include/sys/types.h:47:26: 
machine/ansi.h:


$ ls -l destdir.xen/usr/include/machine                                        
lrwxr-xr-x  1 reed  wsrc  3 Jul 22 20:19 destdir.xen/usr/include/machine 
-> xen
$ ls -l destdir.xen/usr/include/xen      
ls: destdir.xen/usr/include/xen: No such file or directory

What is supposed to populate that?

Any ideas?

Thanks in advance,

Jeremy C. Reed