The file RootUseFile.cmake includes RootNewMacros.cmake, which is supposed to be internal to ROOT and depends on ROOT's own build options to work properly. For example, it depends on explicitlink=ON to actually link any libraries specified as dependencies in ROOT_LINKER_LIBRARY. This is a build option of ROOT that dependent projects most likely won't have, leading to broken library dependencies in CMake. The RootNewMacros.cmake file also pollutes dependent projects with ROOT internal variables and could interfere with other settings (e.g. it unsets CMAKE_VERBOSE_MAKEFILES, and CMAKE_INCLUDE_CURRENT_DIR, which could break user projects).