Avoid collisions between parallel installations of Cygwin

[Earnie Boyd]

Quoting Corinna Vinschen <corinna-cygwin@cygwin.com>:

>
> I still think, however, that, even if we make it optional, the default
> should be switched on.
>

I agree to the default being on is the better choice.

> And I'm still not sure about the best way to set the option.  A
> configuration file will slow down Cygwin's startup somewhat more.  Using
> the registry for that doesn't have appeal either.  Would a CYGWIN option
> not really make most sense?
>

I think that the CYGWIN variable is the better choice.

--
Earnie