These files are from the SoundTouch library (http://www.surina.net/soundtouch/),
and are extracted from the revision r222 of the svn repository at
https://soundtouch.svn.sourceforge.net/svnroot/soundtouch/trunk.

The whole library is not used, only the relevant files are imported in the tree,
using the script `update.sh`. Some changes have been made to the files, using
the patch `moz-libsoundtouch.patch`. We also use a custom soundtouch_config.h.