small bug report for 5.02

[Simon Marlow]

> Dear  ghc-5.02-linux-i386-unknown,
> 
> Here is quite a simple bug report.
> 
>   main = putStr $ shows ((head xs)+(last xs)) "\n"
>                                           where xs = [1..99000]
>   ghc -c Main.hs
>   ghc -o run Main.o
>   ./run +RTS -M100k -RTS
>   99001
>   ./run +RTS -M300k -RTS
>   Heap exhausted;
>   Current maximum heap size is 299008 bytes;

This is a minor mishap in the heap size calculations, caused by the fact
that the maximum heap size you specified in the first test (100k) is
smaller than the minimum allocation area size (256k).  I've fixed the
bug, it should at least report a heap-size exhaustion in both cases.

Cheers,
	Simon