mom5: should we explicitly add netcdf-c's include directory in the SPD?

[harshula]

GCC compiles contain the Makefile snippet:

CFLAGS += $(shell nc-config --cflags)

that results in the following being added:

-I$SPACK/opt/spack/linux-debian12-x86_64/gcc-12.2.0/netcdf-c-4.7.4-jzburrwbsqhi6cjth7nm4zdnunhcyhaq/include -I$SPACK/opt/spack/linux-debian12-x86_64/gcc-12.2.0/hdf5-1.12.2-igvxfglba4p6pcufko2mbprzeampoljh/include

Instead, should we explicitly add netcdf-c's include directory? e.g. (spec["netcdf-c"].headers).cpp_flags

[harshula]

1. mpicc appears to compile the C files without explicitly needing netcdf-c's include directory.

2. pio.h contains:

#include <netcdf.h>

[aidanheerdegen]

Turns out there is very limited use of the netCDF C interface in MOM5 itself (or FMS as that is where this comes from):

https://github.com/mom-ocean/MOM5/blob/master/src/shared/mosaic/read_mosaic.c#L27

There is widespread use in the tools subdirectory, but none of that is used directly by MOM5. The only use of read_mosaic in the code is also in the tools subdirectory

https://github.com/search?q=repo%3Amom-ocean%2FMOM5%20read_mosaic&type=code

apart from compiling EBM (mom5_ebm_compile.csh) which is not relevant.

From the limited searching I've done above it seems to me that read_mosaic.c is not required for MOM5, but it is included in the generic build of FMS because that is used for a number of builds.