Frederick,

Thanks you gave me exactly the information which I was missing. I could not 
find in the mailing list any reference that current xsrc will not run on 1.6ZE

> >
> > I try to build a new X in usr/src/xsrc/make
> > the 1.6.1 ZE (GENERIC) i386
>
>What does that mean, exactly? "uname -sr" on current of Nov. 8 reports
>"NetBSD 1.6ZE". There is no such thing as "1.6.1 ZE".

Sorry it was 1.6ZE


>Based on your apparent confusion, I bet you have a NetBSD 1.6.1
>userland with 1.6ZE kernel. "xsrc" triggers the build of "xsystrace"
>based on the result of "uname", which is based on the kernel version,
>but the compiler and headers are still 1.6.1, and "xsystrace" won't
>build on 1.6.1.
>
>The root problem is something of a known problem. It's been suggested,
>at times, to let "uname"'s result be compiled in, or come from "libc".
>
>If my guess is correct, you seem to have two ways to go... 1) Take
>your kernel back to 1.6.1_RC1; or 2) take your kernel and userland up
>to current (which is already 1.6ZF).

In the meantime I did a upgrade to 1.6ZF. After that I was able to 
/usr/xsrc/make build.

May be just for curiosity:
It seems that /usr/pkgsrc/XF86Setup does not like the new environment.

eagle# cd XF86Setup
eagle# make clean
===> Cleaning for XF86Setup-3.3.6nb1
eagle# make
===> This package doesn't work with your X11 distribution.

However, I was able to make a initial x11 configuration using xf86cfg

Regards jakob