> gdb /usr/X11R6/bin/XF86_SVGA XF86_SVGA.core
> 
> Program terminated with signal 4, Illegal instruction.
> #0 0xcf035 in ?? ()
> (gdb) bt
> #0 0xcf035 in ?? ()
> #1 0x1033b0 in ?? ()
> #2 0xff6b9 in ?? ()
> #3 0xbd2c in ?? ()
> #4 0x10da in ?? ()

This could be hard to use, because you don't have debugging symbols.

I can't remember from your first posting; but I assume you can duplicate
this problem.

Rebuild your XF86_SVGA with debugging. Maybe by adding the following to
your mk.conf:
COPTS+=         -g
LDFLAGS+=       -g

   Jeremy C. Reed
   http://www.reedmedia.net/