[Cmake] cmAddTestCommand breaks

[Brad King]

> In cmAddTestCommand.cxx:82, there is
>      std::ios_base::app
> which is the correct, standards-compliant way of specifing the append
> mode. Unfortunately, with gcc 2.95.2 (under FreeBSD at least), this
> fails. std::ios::app works, though.
> 
> What can and should be done to fix this?
This has been fixed in a large change Bill Hoffman is working on that has
yet to be checked in.  It will hopefully be ready today sometime.

-Brad