Setting um makefile for dmd

[Namal via Digitalmars-d-learn]

Hello,

i get myself a nice makefile from here:
https://gist.github.com/darkstalker/2221824

How can I modify it so that I can use the run option of dmd? I 
tried to add another compiler flag variable which would be only 
used with run but then it messed with -of$@ option and said it 
couldn't read it.

Thanks