Log Message:
Update helpdeco to version 2.1.3.  Changes include:
* helpdec1.c, helpdeco.h: Improve const correctness - thanks to
  Markus Elfring (elfring) for the tip
* compat.c: Apply patch from Dirk Jagdmann (doj) to fix pointer
  flibbling
* splitmrb.c: Apply patch from Dirk Jagdmann (doj) to fix HOTSPOT
  struct packing with GCC >= 3
* compat.c, compat.h, helpdeco.c, splitmrb.c, zapres.c: Apply patch
  from Dirk Jagdmann (doj) to use POSIX path defines instead of DOS
  ones.
* helpdec1.c, helpdeco.c: Add patch for compiling with GCC 4.0 from
  Andreas Jochens <aj@andaco.de>