…HEMCO

In the CESM model, emissions through HEMCO are provided to GEOS-Chem through the physics buffer and not through the HEMCO subroutine calls. A side-effect of this implementation is that HEMCO versions and GEOS-Chem versions in CESM can be decoupled, and thus hard-dependencies on HEMCO data structures should not apply.

In this particular case, additional ExtState fields in HEMCO are causing CESM build failures in the latest GEOS-Chem version. Most (but not all) subroutines in hco_interface_gc_mod.F90 are unused in CESM and are now blocked off from MODEL_CESM to avoid this hard dependency.

Signed-off-by: Haipeng Lin <[email protected]>