Fix a condition that causes an infinite loop, but only when compiled with

gcc 4.2.4 on x86_32. Thanks to Vitor for hunting this down.

Originally committed as revision 17802 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/wc3movie.c

@@ -293,7 +293,7 @@ static int wc3_read_packet(AVFormatContext *s,
         /* get the next chunk preamble */
         if ((ret = get_buffer(pb, preamble, WC3_PREAMBLE_SIZE)) !=
             WC3_PREAMBLE_SIZE)
-            ret = AVERROR(EIO);
+            return AVERROR(EIO);
 
         fourcc_tag = AV_RL32(&preamble[0]);
         /* chunk sizes are 16-bit aligned */