This function will split up your program into files that the AutoLoader module
can handle. It is used by both the standard perl libraries and by the MakeMaker
utility, to automatically configure libraries for autoloading.
The autosplit interface splits the specified file into a hierarchy rooted at the
directory $dir. It creates directories as needed to reflect class hierarchy, and
creates the file autosplit.ix. This file acts as both forward declaration of all
package routines, and as timestamp for the last update of the hierarchy.
