[CMake] Sourceless targets

[C. Meissa]

Hello Lists,

I have lots of small libraries and sometime it is needed to unify them to a 
main program library e.g. libtest.so for my test program…

I tried
ADD_LIBRARY(test-mainlib SHARED "")
SET_TARGET_PROPERTIES( test-mainlib PROPERTIES OUPUT_NAME libtest )

But this does not work due to "Cannot determine link language for target"
Thanks for your help!

Best Regards
C.M.