
Allow Spack to build with ROOT as an external dependency by setting LD_LIBRARY_PATH: given that the external package was not built by Spack, dependents would not be able to locate libraries using RPATHs when running ROOT binaries.
Allow Spack to build with ROOT as an external dependency by setting LD_LIBRARY_PATH: given that the external package was not built by Spack, dependents would not be able to locate libraries using RPATHs when running ROOT binaries.