lavc/libaribcaption: switch all `bool` context variables to `int`

On some environments, a `bool` variable is of smaller size than `int`.
As AV_OPT_TYPE_BOOL is internally handled as sizeof(int), if a `bool`
option was set on such an environment, the memory of following
variables would be filled. Additionally, set values may be destroyed
by av_opt_copy().

Signed-off-by: TADANO Tokumei <aimingoff@pc.nifty.jp>
(cherry picked from commit 82faba8a6c)

libavcodec/libaribcaption.c

@@ -68,14 +68,14 @@ typedef struct ARIBCaptionContext {
 
     int subtitle_type;
     int encoding_scheme;
-    bool ass_single_rect;
+    int ass_single_rect;
     char *font;
-    bool replace_fullwidth_ascii;
-    bool force_stroke_text;
-    bool ignore_background;
-    bool ignore_ruby;
+    int replace_fullwidth_ascii;
+    int force_stroke_text;
+    int ignore_background;
+    int ignore_ruby;
     float stroke_width;
-    bool replace_drcs;
+    int replace_drcs;
 
     int64_t pts;
     AVRational time_base;