No xf86config file --- ??

["vishnuvaradan vishnuvaradan" <vishnuvaradanr@xxxxxxxxx>]

Hi All

I have crosscompiled xfree4.7.0 for ppc , merged with the file system and i can able to boot an embedded board with ppc thru nfs

But, there is no xf86config file

I have tried all the commands , 
 XFree86 -configure -
/bin/ash: XFree86: not found

here is the list of directories and files

/usr/X11R6/lib/X11 # ls
Cards          Xcms.txt       getconfig      twm            xman.help
Options        app-defaults   lbxproxy       x11perfcomp    xserver
XErrorDB       config         locale         xdm            xsm
XF86Config.98  doc            proxymngr      xedit
XF86Config.eg  etc            rgb.txt        xinit
XKeysymDB      fs             rstart         xkb


/etc/X11 # ls
app-defaults  proxymngr     xdm           xserver
fs            rstart        xinit         xsm
lbxproxy      twm           xkb

for manual creation if i try cp -a /usr/X11R6/lib/X11   /etc/X11  its displaying cp: unable to open `/etc/X11/XF86Config.eg': Read-only file system


How can i create xf86config file ??

please help me

Thanks