[QBS] How to generate 2 objects from the same source file

[Ch'Gans]

Hi there,

For testing the clang DB generator[1] I would like to generate 2
objects from the same source file (clang tools should normally check
the same source file twice with the 2 different compile commands).

Is there a simple way to do that?
To keep it simple i would like first.o and second.o to be generated
with different preprocessor flags.

Thanks
Chris