RFC: Use tree/rtx/rtvec instead of "union ...*'" in headers.

[Neil Booth]

Kelley Cook wrote:-

> > This has been hanging around in my tree now for a week or so,
> > but mainline _still_ doesn't build on Cygwin, even with an updated
> > gawk (now it is OPT__version that is missing for some silly reason
> > <sigh>...). Ergo, completely untested, though it seems to compile
> > just fine.
> 
> Yeppers,
> 
> http://gcc.gnu.org/ml/gcc-patches/2003-06/msg02230.html
> 
> should finally fix it, though.

I've applied it.

Neil.