Various small fixes to the builtin module to ensure no buffer overflows.

- chunk #1:
  Proper casting to ensure no truncation, and hence no surprises, in the
  comparison.

- chunk #2:
  The id() function guarantees a unique return value for different objects.
  It does this by returning the pointer to the object. By returning a PyInt,
  on Win64 (sizeof(long) < sizeof(void*)) the pointer is truncated and the
  guarantee may be proven false. The appropriate return function is
  PyLong_FromVoidPtr, this returns a PyLong if that is necessary to return
  the pointer without truncation.

- chunk #3:
  Ensure no overflow in raw_input(). Granted the user would have to pass in
  >2GB of data but it *is* a possible buffer overflow condition.