Fixed return values on testhotplug mainline.

test/testhotplug.c

@@ -126,6 +126,8 @@ main(int argc, char *argv[])
     }
 
     SDL_QuitSubSystem(SDL_INIT_VIDEO | SDL_INIT_JOYSTICK);
+
+    return 0;
 }
 #else
 
@@ -133,7 +135,7 @@ int
 main(int argc, char *argv[])
 {
     SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL compiled without Joystick support.\n");
-    exit(1);
+    return 1;
 }
 
 #endif