finding strict aliasing problems

[Joe Buck]

> | Let me say that I think that 3.0 should ship with alias analysis
> | turned on.  If we do a .0 release every decade, and if we want the .0
> | release to have the major changes that might throw people, then,
> | clearly, 3.0 should turn it on, otherwise, we have to wait a decade.
> 
> I second both Jakub and Mike.

Oh, I agree, despite my concerns; 3.0 is a good time to make a major
change.  But the change should appear near the top of announcements,
NEWS files, and release notes, because folks who like to write lots
of tricky casts need to know.