CLM3.0 was released 15 years ago, and is no longer supported in any fashion. It's not surprising that the Makefile would need to be updated, and that there might be problems in getting it to build and run. We can't help in that regard. Is there a reason you really need to use a fifteen year old model? If so, if there's someone else using CLM3.0 they might be able to help. We do have support for CLM4.0 that's part of the CESM2.1.1 release.