[CMake] Conditional transitive link libraries

[Daniel Wirtz]

Hey,

so while this is a suitable solution for 3-level transitive packages, it 
will break as soon as you have
more than that..
i realized there is no "native" solution to the problem, and the 
solution in the below link indeed helps for many cases.
however, facing a ever-more cmake'ified software environment (which is 
good!), we will sooner or later encounter
"downstream" package constellations that have transitive linking into 
cmake packages over more than 3 levels..
so i think it is worth while discussing/thinking about a suitable design 
to include.

best,
Daniel

> Daniel Wirtz wrote:
>
>> Hello all,
>>
>> I'm struggling with the CMake "Config"-based package description when
>> using two depending packages where the upstream package has optional
>> link libraries.
> For reference, you have the right answer and the link to the right
> documentation on SO
>
>   http://stackoverflow.com/questions/30568733
>
> Thanks,
>
> Steve.
>