write_basic_package_version_file doesn't write configs that are consistent with module mode FindXXX standards
FindXXX has pretty standard support for old school defines like: Foo_LIBRARIES Foo_INCLUDES etc.
but when a library is exported for config mode, typically it only concerns itself with the target. Using the standard method to generate the configs, (ie. write_basic_package_version_file), should cover the same basics found in module mode scripts so that "find_package" will be consistent.