[PATCH] Repair TYPE_REF_CAN_ALIAS_ALL machinery

[Richard Kenner]

    As a general statement, we shouldn't need TYPE_REF_CAN_ALIAS_ALL, we
    handle the same thing in other languages without it.  

No.  Other languages don't have that concept.  In C, (char *) is presumed
to alias to everything, but that's (as has been said) really an attribute
of "char", not the pointer: *all* pointers to char behave that way.

In Ada, we have the situation where we have a type T and most pointers to
T are fine, but *one particular* type that points to T has this behavior.
That's a very different model.