Subproject fixes

I think the issue mentionned here was fixed by Daniel solely by changing the line above :
from: list(APPEND ALL_CPP_TESTS ${NAME})
to: list(APPEND ALL_CPP_TESTS ${PROJECT_NAME}_${NAME})
With this change, these 3 lines should not cause trouble. HOWEVER, I would still remove them. They are creating extra targets which depend on the "real" targets, but you can never rely on having them because a different project might have set them already. So this is just bloating up the list of targets and may cause unnecessary confusion.