The changes in this tag are equivalent to those in
https://github.com/ESMCI/cime/pull/3093

For present-day compsets, the CESM land group wants
DATM_CLMNCEP_YR_ALIGN to match DATM_CLMNCEP_YR_START for present-day
compsets. This will make the model year align with the forcing year. For
example, if RUN_STARTDATE is set to 2000-01-01, then the model will use
year-2000 atmospheric forcing data in the first year, etc.