av_log() patch by (Michel Bardiaux <mbardiaux at peaktime dot be>)

Originally committed as revision 2840 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffmpeg.c

@@ -2352,7 +2352,7 @@ static void opt_output_file(const char *filename)
     if (!strcmp(filename, "-"))
         filename = "pipe:";
 
-    oc = av_mallocz(sizeof(AVFormatContext));
+    oc = av_alloc_format_context();
 
     if (!file_oformat) {
         file_oformat = guess_format(NULL, filename, NULL);