Small modernisation of CMake target usage in place of variables
This is an "appendix" to !867 (merged) and the second part of cherry-picking !866 (closed) before tackling the full CUDA modernisation.
- CMake minimum version bump to 3.12 to support future CUDA modernization
- Use of proper CMake imported targets for ROOT when used
- Use, as far as possible, linking to CMake target names rather than trying to fill variables
- Major cleanup of VGDML build
There were a couple of items that couldn't be cherry-picked because the current FindCUDA
is a mess, specifically:
- Removal to testing of the
cudauserlib
target - Remove test CUDA code/kernels from vecgeomcuda libraries
FindCUDA
and its adaptions are just too broken to cope with this.
This should ideally be merged after !867 (merged), and may require a rebase before that anyway!