Since the sdl to target tree move, the main thread cannot be removed anymore,

since it's now the default thread which is implicitely created by starting the sim.

This caused a segfault that r26283 tried to fix. Revert r26283 and protect
the main thread from being removed.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@26315 a1c6a512-1295-4272-9138-f99709370657

apps/misc.c

@@ -256,7 +256,6 @@ static bool clean_shutdown(void (*callback)(void *), void *parameter)
     (void)parameter;
     bookmark_autobookmark(false);
     call_storage_idle_notifys(true);
-    exit(0);
 #else
     long msg_id = -1;
     int i;

firmware/target/hosted/sdl/button-sdl.c

@@ -176,7 +176,6 @@ void gui_message_loop(void)
             case SDL_QUIT:
             {
                 sim_exit_irq_handler();
-                SDL_Quit();
                 exit(EXIT_SUCCESS);
                 break;
             }

firmware/target/hosted/sdl/thread-sdl.c

@@ -566,7 +566,12 @@ void remove_thread(unsigned int thread_id)
 
 void thread_exit(void)
 {
-    remove_thread(THREAD_ID_CURRENT);
+    struct thread_entry *t = thread_id_entry(THREAD_ID_CURRENT);
+    /* the main thread cannot be removed since it's created implicitely
+     * by starting the program;
+     * it has no valid jumpbuf to exit, do nothing for now */
+    if (t != &threads[0])
+        remove_thread(t->id);
 }
 
 void thread_wait(unsigned int thread_id)