gcd 0 0 = 0

George Russell ger@tzi.de
Mon, 17 Dec 2001 18:05:41 +0100

I've reconsidered my earlier position and think now that the Prelude is wrong to make
gcd 0 0 an error, and should return 0.  It probably doesn't make much difference to 
anyone, but it's like 1 not being a prime; it may be slightly harder to explain, but it
makes the maths come out nicer and is in the end a simplification.