[project @ 2001-07-20 15:22:21 by simonpj]

[project @ 2001-07-20 15:22:21 by simonpj]
-----------------------
	Get rid of ArityAtLeast
	-----------------------

Now that we have CgInfo, with the exact code-generator arity
for the value, we don't need the distinction between ArityAtLeast
and ArityExactly in the ArityInfo field of an IdInfo.

This commit makes

	type ArityInfo = Maybe Arity

and propagates this change consistently through the compiler.