dpkg-reconfigure xserver-xorg fails

[hendrik@topoi.pooq.com]

I'm running etch on an AMD-64.  I have (mostly) finished 
the xorg6.9 -> 7.0 transition, which you have probabl 
head about in mu other messages on this list.  Have installed 
nvidia-kernel-drivers after building them from the nvidia-kernel-source 
package.

I still have to get glx working, server-side.  So on the off-chance that 
the glx module has become unrequested during the upgrade, I try

  dpkg-reconfigure xserver-xorg

which complains

xserver-xorg postint warning: not updating /etc/X11/X; file has been
  customised

Well, it hasn't been.  Not by me, anyway, unless using dpkg-reconfigure 
counts as customisation.  (and it appeared that default loading of glx 
had been specified, so I may have another problem with the nividia 
stuff).

In the old days of Xfree86, I could read a file with a name 
like Xfree86.conf for instructionls how to reset the customisation flag.

But /etc/X11/X is a binary file.  Using
   less /etc/X11/X
to find out how to decustomise doesn't help.

But /etc/X11/xorg.conf says to run
  dpkg-reconfigure -phigh xserver-xorg
to get around a similare problem with /etc/X11/xorg.conf.
but that just gives the same message I complained about at the 
start of this posting. I suspec the -phigh is just to avoid lots of 
detailed questions, rather than make anything work.  What do I do to get 
past this obstacle?

-- hendrik