TextIO.scanStream is wrong

[Stephen Weeks]

> Ok,  I  have  been thinking about this for a bit, and I finally realized that
> something is REALLY  wrong  with  MLton  TextIO.   For  a  concrete  example,
> consider the following code:
...
> Don't get me wrong: I think that the TextIO.scanStream interface is  slightly
> goofy  (i.e.,  I  can't  off  hand  think of a reasonable way to make it work
> fast), but what we have is clearly wrong.

I agree that what was there was wrong.  I have fixed the basis library and it
now works on this example.  If you need the fix now, lemme know and I'll make up
an RPM.  Else, it'll be there with the next snapshot.