avformat/icoenc: Add deinit function

Prevents memleaks in situations where the trailer isn't written, e.g.
because of errors during writing the header.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/icoenc.c

@@ -183,11 +183,16 @@ static int ico_write_trailer(AVFormatContext *s)
         avio_wl32(pb, ico->images[i].offset);
     }
 
-    av_freep(&ico->images);
-
     return 0;
 }
 
+static void ico_deinit(AVFormatContext *s)
+{
+    IcoMuxContext *ico = s->priv_data;
+
+    av_freep(&ico->images);
+}
+
 AVOutputFormat ff_ico_muxer = {
     .name           = "ico",
     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft Windows ICO"),
@@ -199,5 +204,6 @@ AVOutputFormat ff_ico_muxer = {
     .write_header   = ico_write_header,
     .write_packet   = ico_write_packet,
     .write_trailer  = ico_write_trailer,
+    .deinit         = ico_deinit,
     .flags          = AVFMT_NOTIMESTAMPS,
 };