Log Message:
Upgrade arena from version 0.9.8 to 0.9.9.

Changes in this version include:

	This release fixes a possible double free problem in the
	printf() implementation.  The problem occurred when more
	conversion specifiers than function arguments were present and
	the format required a cast from the dummy void value used by
	the implementation to another type.  Thanks to Dennis Heuer
	for reporting the problem.

	Also based on a suggestion by Dennis, the interpreter no
	longer allows non-terminated escape sequences in string
	literals.  In other words, a string literal may no longer end
	in a backslash character.

	Alistair Crooks provided a couple of new example scripts that
	include interfacing to native C libraries under NetBSD.  He
	also suggested to allow hexadecimal integer literals.  These
	are now allowed and need to be prefixed with "0x".  For
	example, "0xFF" or "0xff" is the same as writing \ 
"255".

	Fabian Tschiatschek provided a patch to allow extra arguments
	to be passed to map, filter, foldl, foldr, drop_while, and
	take_while.  These are passed down into the function provided
	as the first argument.  Fabian also noticed that the
	documentation and implementation of foldr did not agree about
	the order of arguments.  The implementation was changed to
	match the language manual.

	There is a new library function called is_null that can check
	whether a memory resource contains a C NULL pointer.

patch-ab has now been removed since, with the inclusion of is_null(), there
is no need for it.