[racket] Checking whether running from DrRacket.

> I can do this. And this solves half the problem: the main is not run
> from DrRacket. That's what I want.
>
> However, if I generate an executable, then the main is not executed
> when I run the executable either. This is not what I want.


Hi Pierpaolo,

Agreed.  That's surprising: I also expected the main submodule to run
from an executable!  This sounds like a bug.  Let's hear from the
others to make sure about that one.