added "new" behaviour for Policy CMP0077 which allows to control the build options by variables if lib is used by FetchContent of a super project
added "new" behaviour for Policy CMP0077 which allows to control the build options by variables if lib is used by FetchContent of a super project

libexpat/libexpat,libexpat/libexpat,libexpat/libexpat,libexpat/libexpat,libexpat/libexpat,libexpat/libexpat