The main change is cleanup of the visualConfigs and setting up alpha correctly there to match the visuals being added earlier (so the default visual has a corresponding GLX visual)
(cherry picked from commit 7351db5c8746be30a4047469ee9b50bc19e62a89)
Add a setVisualConfigs that is called before the fbScreenInit, to setup the __GLXvisualConfigs.
(cherry picked from commit fc86f9e4482043eca76d9d7a96e166be1aabf674)