Configure check for NC4 chunking consts

[jayeshkrishna]

Adding a configure check (and appropriate warning messages) for NetCDF4
chunking constants.

Fixes #523

[dqwu]

@jayeshkrishna
This PR works on Chrysalis, but the following CMake warning message is not found in bld/spio.bldlog.xxxx.gz:
message(WARNING "NetCDF4 is available but NetCDF4 chunking constants are not defined (limits chunking support)")

[jayeshkrishna]

Are you suppressing warnings by any chance (-Wno-dev or something similar)?

[dqwu]

Are you suppressing warnings by any chance (-Wno-dev or something similar)?

-Wno-dev is added by CIME in Tools/Makefile:

CMAKE_OPTS += -Wno-dev -D CMAKE_Fortran_FLAGS:STRING="$(FFLAGS) $(EXTRA_PIO_FPPDEFS) $(INCLDIR)" \
	      -D CMAKE_C_FLAGS:STRING="$(CFLAGS) $(EXTRA_PIO_CPPDEFS) $(INCLDIR)" \
	      -D CMAKE_CXX_FLAGS:STRING="$(CXXFLAGS) $(EXTRA_PIO_CPPDEFS) $(INCLDIR)" \
	      -D CMAKE_VERBOSE_MAKEFILE:BOOL=ON \
	      -D GPTL_PATH:STRING=$(INSTALL_SHAREDPATH) \
	      -D PIO_ENABLE_TESTS:BOOL=OFF \
	      -D PIO_USE_MALLOC:BOOL=ON \
	      -D USER_CMAKE_MODULE_PATH:LIST="$(CIMEROOT)/CIME/non_py/src/CMake;$(EXTERN_PATH)/parallelio/cmake"

[dqwu]

@jayeshkrishna

Even without the "-Wno-dev" flag, the CMake configuration output is different on GCE and Chrysalis.

GCE:

-- Found NetCDF_Fortran: /nfs/gce/projects/climate/software/linux-ubuntu20.04-x86_64/netcdf/4.8.0c-4.3.1cxx-4.5.3f-parallel/mpich-4.0/gcc-11.1.0/lib/libnetcdff.a  
...
-- NetCDF Fortran library dependencies: ****
-- Checking Whether the NetCDF4 chunking constants are available
-- Checking Whether the NetCDF4 chunking constants are available - yes
-- Disabling support for PnetCDF

Chrysalis

-- Found NetCDF_Fortran: /gpfs/fs1/soft/chrysalis/spack/opt/spack/linux-centos8-x86_64/intel-20.0.4/netcdf-fortran-4.4.4-tplolxh/lib/libnetcdff.so  
-- NetCDF Fortran library dependencies: ****
-- Disabling support for PnetCDF

That is, the expected messages "Checking Whether the NetCDF4 chunking constants ..." are not shown on Chrysalis.

[jayeshkrishna]

The current configure checks only enable NetCDF4 if NetCDF4 parallel I/O is available. Since chrysalis does not support parallel I/O for NetCDF (netcdf_par.h is missing in the Fortran include dir) the chunking const check is not run too. This check (for checking NetCDF parallel I/O support) needs to be fixed in future.
So the difference in behavior between the machines is not due to changes in this PR.

[dqwu]

This PR does not need to change for now.