DIP(?) Warning to facilitate porting to other archs

[bearophile via Digitalmars-d]

Temtaime:

> I think it's need to have -w64(or other name, offers ?) flag 
> that warns if code may not compile on other archs.

It's a problem and I'd like some way to compiler help solving 
such problems.

I suggested this, that was refused (I don't remember who reopened 
it):
https://issues.dlang.org/show_bug.cgi?id=5063

Bye,
bearophile