Error: unrecognized switch '--DRT-oncycle=print' => where is switch defined?

[Steven Schveighoffer via Digitalmars-d-learn]

On 5/15/17 6:37 PM, Timothee Cour via Digitalmars-d-learn wrote:
> Getting this:
>
> ```
> Deprecation 16211 warning:
> A cycle has been detected in your program that was undetected prior to DMD
> 2.072. This program will continue, but will not operate when using DMD 2.073
> to compile. Use runtime option --DRT-oncycle=print to see the cycle details.
> ```
>
> Where is ` --DRT-oncycle=print` defined? can't find it even on DMD64 D
> Compiler v2.075.0-devel-c3ddfaa-dirty
>
> And adding the switch results in:
> Error: unrecognized switch '--DRT-oncycle=print'
>

You pass it to your actual program, not the compiler. It's a D Runtime 
(i.e. DRT) switch.

-Steve