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.

Title SDL 1.2.9
Version 1
Description SDL Library for Mac OS X (http://www.libsdl.org)
DefaultLocation /Developer/Documentation/SDL
Diskname (null)
DeleteWarning 
NeedsAuthorization YES
DisableStop NO
UseUserMask YES
Application NO
Relocatable NO
Required NO
InstallOnly NO
RequiresReboot NO
InstallFat NO