GLX and "ssystem"- how?

[jim@short.circuit.com]

GLX. How do I get it to work with "ssystem"?

I have installed utah-glx and loading gtx.so in XF86Config, which
gets to the splash screen, but ssystem quits with the error:

X Error of failed request:  GLXUnsupportedPrivateRequest
  Major opcode of failed request:  148 (GLX)
  Minor opcode of failed request:  17 (X_GLXVendorPrivateWithReply)
  Serial number of failed request:  168
  Current serial number in output stream:  168

The video card is an S3 Trio/64, I've tried both xserver-svga and xserver-s3
with the same results.