This update gets ac.scm back into being a module, so to run Arc using this patch go back to using "mzscheme" as the command to run:
~/plt-4.1.5/bin/mzscheme -f as.scm
but no "-m", as that option has changed in plt4.
Getting ac.scm back into a module makes this version almost twice as fast as the last version of the patch. Unfortunately that's still not very good: it's taking 3.5 times as long to get to the Arc REPL prompt with this patch using plt4 as it does with the unmodified Arc using plt3.
