[MLton] bool array size

[Stephen Weeks]

> Yes, the same thing with regards to arrays using an extra level of indirection
> is still happening with 20051202.  If I have an array with elements of type
> 	{ key: Word.word, ord: int }
> then it uses 16 bytes per element.  That must be 4 for the pointer in the
> array and 12 (2 4-byte fields and one 4-byte header) for the tuple/record
> being pointed to.

That is a possibility.  It all depends on whether MLton's flattening
optimization is smart enough to flatten the elements into the array.