HandleEvent() returns done each time it is called. If done was set to 0 the program should quit, but because done is not checked until *all* events are handled a following event can reset done to 1 and prevent the program from terminating when told to. I fixed the while loop that handles events to check for the state of done after handling each event. That could leave some events unhandled when the program exits, but it ensures that the program will exit.

--- a/test/testgl.c	Mon Feb 11 21:06:32 2008 +0000
+++ b/test/testgl.c	Wed Feb 20 23:27:33 2008 +0000
@@ -666,7 +666,7 @@
         }
 
         /* Check if there's a pending event. */
-        while (SDL_PollEvent(&event)) {
+        while (!done && SDL_PollEvent(&event)) {
             done = HandleEvent(&event);
         }
         ++frames;