Build warning fixes for gcc-11.3

test/testautomation_rect.c

@@ -707,7 +707,7 @@ int rect_testIntersectRectEmpty (void *arg)
 int rect_testIntersectRectParam(void *arg)
 {
     SDL_Rect rectA;
-    SDL_Rect rectB;
+    SDL_Rect rectB = {0};
     SDL_Rect result;
     SDL_bool intersection;
 
@@ -962,7 +962,7 @@ int rect_testHasIntersectionEmpty (void *arg)
 int rect_testHasIntersectionParam(void *arg)
 {
     SDL_Rect rectA;
-    SDL_Rect rectB;
+    SDL_Rect rectB = {0};
     SDL_bool intersection;
 
     /* invalid parameter combinations */