XQuartz: Call setVisualConfigs in InitOutput, and only when GLXEXT is defined.

(cherry picked from commit 97173d4eda)

hw/xquartz/darwin.c

@@ -229,8 +229,6 @@ static Bool DarwinAddScreen(int index, ScreenPtr pScreen, int argc, char **argv)
 
     miSetPixmapDepths();
 
-    setVisualConfigs();
-
     // machine independent screen init
     // setup _Screen structure in pScreen
     if (monitorResolution)
@@ -595,6 +593,10 @@ void InitOutput( ScreenInfo *pScreenInfo, int argc, char **argv )
     for (i = 0; i < NUMFORMATS; i++)
         pScreenInfo->formats[i] = formats[i];
 
+#ifdef GLXEXT
+    setVisualConfigs();    
+#endif
+
     // Discover screens and do mode specific initialization
     QuartzInitOutput(argc, argv);