[MLton] bug in Socket structure signture

[Stephen Weeks]

> It looks to me like the basis library spec for the socket structure
> is wrong.  Note that Socket.recvVecFrom (and all its friends) claim
> to return a result which includes an address which is polymorphic
> but such things do not exist.
...
> Am I missing something?

I don't think so.  I think it is simply a (family of) typo(s) in the
SOCKET signature.  I checked in a fix to the MLton basis
implementation -- tweaking the SOCKET signature is all that was
required.