fftools: replace fall-through comments

fftools/cmdutils.c

@@ -1267,7 +1267,7 @@ unsigned stream_specifier_match(const StreamSpecifier *ss,
                 break;
             }
         }
-        // fall-through
+        av_fallthrough;
     case STREAM_LIST_GROUP_IDX:
         if (ss->stream_list == STREAM_LIST_GROUP_IDX &&
             ss->list_id >= 0 && ss->list_id < s->nb_stream_groups)

fftools/ffmpeg_filter.c

@@ -27,6 +27,7 @@
 #include "libavfilter/buffersink.h"
 #include "libavfilter/buffersrc.h"
 
+#include "libavutil/attributes.h"
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/bprint.h"
@@ -2572,6 +2573,7 @@ static void video_sync_process(OutputFilterPriv *ofp, AVFrame *frame,
             delta0 = 0;
             ofp->next_pts = llrint(sync_ipts);
         }
+        av_fallthrough;
     case VSYNC_CFR:
         // FIXME set to 0.5 after we fix some dts/pts bugs like in avidec.c
         if (frame_drop_threshold && delta < frame_drop_threshold && fps->frame_number) {

fftools/textformat/tf_ini.c

@@ -26,6 +26,7 @@
 
 #include "avtextformat.h"
 
+#include "libavutil/attributes.h"
 #include "libavutil/bprint.h"
 #include "libavutil/opt.h"
 #include "tf_internal.h"
@@ -74,7 +75,7 @@ static char *ini_escape_str(AVBPrint *dst, const char *src)
         case '=':
         case ':':
             av_bprint_chars(dst, '\\', 1);
-            /* fallthrough */
+            av_fallthrough;
         default:
             if ((unsigned char)c < 32)
                 av_bprintf(dst, "\\x00%02x", (unsigned char)c);