Introduced RAJA_IN_PACKAGE to allow for linking to an in-package dependency of RAJA (eg. Spack)
RAJA looses the source directory, so need to remind it where the BabelStream source is to make sure it treats the source as CUDA NB: The RAJA CUDA build might be broken at this time. See https://github.com/LLNL/RAJA/issues/1296 Workaround below worked for us https://github.com/LLNL/RAJA/pull/1302
Create subdir for each cpp-based implementation