[project @ 1999-05-11 16:33:35 by keithw]
(this is number 3 of 9 commits to be applied together)
Following Haskell 98, if the module declaration is omitted it now
defaults to "module Main(main) where", rather than the previous
default of exporting everything.
Furthermore, "module Main where" also defaults to exporting just
Main.main rather than everything in the module (modules other than
Main behave as normal). This permits the usage inference to give
better results for the Main module, since exported functions get
worse types than nonexported functions.