Empty class passing details

[Mark Mitchell]

We should also say what to do with return values.  And, I think in the
spirit of easy reading, we should say:

  as thought it were a struct containing a single char, i.e., 
  `struct S { char c; };'

The value of the char member are unspecified.  Similar language for
return values.  This suggests an obvious, well-defined implementation.

If there are associated performance issues, they don't really matter
-- that was the unanimous conclusion of the experts we polled, and the
reason for simplifying this stuff anyhow.  Let's make it
super-simple. :-)

--
Mark Mitchell                   mark at codesourcery.com
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