In testdyngl.c the event type was being anded (&) with SDL_KEYDOWN and if the result was none zero the program was quiting. This is very weird because it was working earlier this week. I added some more trace code to SDL_x11events.c In SDL_X11opengl.c I modified SDL_GL_GetSwapInterval() so that it returns a pretty good value even if you have the SGI swap extension instead of the MESA swap extension. I just saved the value you set and return it too you.

--- a/test/testdyngl.c	Fri Mar 07 21:01:54 2008 +0000
+++ b/test/testdyngl.c	Fri Mar 07 23:57:15 2008 +0000
@@ -180,7 +180,7 @@
         SDL_GL_SwapBuffers();
 
         while (SDL_PollEvent(&event)) {
-            if (event.type & SDL_KEYDOWN)
+            if (event.type == SDL_KEYDOWN)
                 done = 1;
         }