Fixed warning C4244: '=': conversion from 'Sint64' to 'int', possible loss of data

(cherry picked from commit 12bab1c981edbd9092d58f8479d00032d248d0ce)

src/video/SDL_stretch.c

@@ -146,9 +146,10 @@ int SDL_SoftStretch(SDL_Surface *src, const SDL_Rect *srcrect,
     int i;                                                                            \
     Sint64 fp_sum_h;                                                                  \
     int fp_step_h, left_pad_h, right_pad_h;                                           \
-    Sint64  fp_sum_w;                                                                 \
+    Sint64 fp_sum_w;                                                                  \
     int fp_step_w, left_pad_w, right_pad_w;                                           \
-    int fp_sum_w_init, left_pad_w_init, right_pad_w_init, dst_gap, middle_init;       \
+    Sint64 fp_sum_w_init;                                                             \
+    int left_pad_w_init, right_pad_w_init, dst_gap, middle_init;                      \
     get_scaler_datas(src_h, dst_h, &fp_sum_h, &fp_step_h, &left_pad_h, &right_pad_h); \
     get_scaler_datas(src_w, dst_w, &fp_sum_w, &fp_step_w, &left_pad_w, &right_pad_w); \
     fp_sum_w_init = fp_sum_w + left_pad_w * fp_step_w;                                \