This is for vbi decoding.  Taken from alevt 1.6.0
Changes:
  * Makefile written from scratch.
  * cache.c:  removed help pages.
  * vbi.c:    removed "static" from vbi_handler
  * export.c: removed "static" from fmt_page

Fixes:
  vbi.c: vbi_open(): BTTV_VBISIZE is _IOR(int) and therefore wants
  a valid (dummy) pointer as arg.
