If you are receiving an error like this in Steam:
libGL error: No matching fbConfigs or visuals found
libGL error: failed to load driver: swrast
Steam: An X Error occurred
X Error of failed request: GLXBadContext
Major opcode of failed request: 152
Serial number of failed request: 50
xerror_handler: X failed, continuing
Steam: An X Error occurred
Try installing the most recent libnvidia-gl-*
i386 package, for example:
sudo apt-get install libnvidia-gl-418:i386