script tweak

build.sh

@@ -318,7 +318,7 @@ if [ ! -d "$dist_dir/$ffmpeg_target" ]; then
   log "Retrieving ffmpeg"
   ffmpeg_url_base="https://github.com/aclap-dev/ffmpeg-static-builder/releases/download/"
   ffmpeg_url=$ffmpeg_url_base/v$package_ffmpeg_build_version/$ffmpeg_target.tar.bz2
-  ffmpeg_tarball=$dist_dir/ffmpeg.tar.bz2
+  ffmpeg_tarball=$dist_dir/$ffmpeg_target.tar.bz2
   wget --show-progress -c -O $ffmpeg_tarball $ffmpeg_url
   (cd $dist_dir && tar -xf $ffmpeg_tarball)
   rm $ffmpeg_tarball