ip 5/5.1

[AlexanderRichert-NOAA]

Just as a headsup, the sp library is deprecated and its functionality is now under ip 5.0 (present in spack-stack-1.8.0; #983). Moving to ip 5.0 should be fairly straightforward, and involves removing/replacing find_package(sp) and target_link_libraries(sp:sp_*). For ip 5.1, which will hopefully be in spack-stack-1.9.0, the sp functionality is in a module and therefore must be accessed through use sp_mod.