update SDL soruce to 2.0.14

Edward Rudd

2021-06-15 dec7875a6e23212021e4d9080330a42832dfe02a

 source/src/test/SDL_test_common.c

@@ -1027,10 +1027,12 @@
        }
        for (i = 0; i < state->num_windows; ++i) {
            char title[1024];
            SDL_Rect r = {
                state->window_x, state->window_y,
                state->window_w, state->window_h
            };
            SDL_Rect r;

            r.x = state->window_x;
            r.y = state->window_y;
            r.w = state->window_w;
            r.h = state->window_h;

            /* !!! FIXME: hack to make --usable-bounds work for now. */
            if ((r.x == -1) && (r.y == -1) && (r.w == -1) && (r.h == -1)) {