* Fixed the BeOS compile typo.

  * Fixed the BeOS compile typo.
  * The ALSA plugin is back.
  * A gift for Gildas: plugins don't rely on backlinking any more. The
    drawback is the dirty magic in include/modules_export.h which has to
    be included whenever a module needs one of the functions in it. But
     a) we should less and less rely on those functions
     b) no plugin code modification was needed

   The BeOS and MacOS X modules may be broken when compiled as plugins,
   I'll check this later when I can reboot under BeOS.