CMake: Export to parent scope only if it exists
CMake: Export to parent scope only if it exists

Former-commit-id: 50247861ed563e18d3b8310f9ad72477c9ab38f7
kmuzalewska/j-pet-framework,kmuzalewska/j-pet-framework,kmuzalewska/j-pet-framework,kmuzalewska/j-pet-framework,kmuzalewska/j-pet-framework