use of the underlying system realloc(). List comprehensions also
benefit. The amount of improvement varies between systems and shows
the greatest improvement on systems with poor realloc() implementations.
+ \method{list.extend()} was also optimized and no longer converts its
+ argument into a temporary list prior to extending the base list.
\item \function{list()}, \function{tuple()}, \function{map()},
\function{filter()}, and \function{zip()} now run several times