Merge branch 'framework/makefile_pnetcdf_test' into develop (PR #1263)

This merge adds a test to the top-level Makefile to ensure that PnetCDF is
available.

With the addition of SMIOL, PnetCDF is required for all builds of MPAS. This
merge prevents build issues that can arise from forgetting the PNETCDF
environment variable or other issues related to finding the PnetCDF library.
If the build of the test program fails, the PnetCDF test C program will be left
in the MPAS-Model directory to aid in troubleshooting.

* framework/makefile_pnetcdf_test:
  Add build check for PnetCDF to top-level Makefile

Author: mgduda

Makefile

@@ -1266,7 +1266,7 @@ ifeq "$(OPENACC)" "true"
 endif # OPENACC eq true
 
 
-pio_test: openmp_test openacc_test
+pio_test: openmp_test openacc_test pnetcdf_test
 	@#
 	@# PIO_VERS will be set to:
 	@#  0 if no working PIO library was detected (and .piotest.log will contain error messages)
@@ -1374,11 +1374,52 @@ mpi_f08_test:
 	$(if $(findstring 1,$(MPAS_MPI_F08)), $(eval MPI_F08_MESSAGE = "Using the mpi_f08 module."), )
 	$(if $(findstring 1,$(MPAS_MPI_F08)), $(info mpi_f08 module detected.))
 
+
+pnetcdf_test:
+	@#
+	@# Create test C programs that look for PNetCDF header file and some symbols in it
+	@#
+ifneq "$(PNETCDF)" ""
+	@echo "Checking for a working PnetCDF library..."
+	@printf "#include \"pnetcdf.h\"\n\
+			&#include \"mpi.h\"\n\
+			&int main(){\n\
+			&    int err, ncid;\n\
+			&    err = ncmpi_create(MPI_COMM_WORLD, \"foo.nc\", NC_NOCLOBBER, MPI_INFO_NULL, &ncid);\n\
+			&    return 0;\n\
+			&}\n" | sed 's/&/ /' > pnetcdf.c
+	@( $(CC) pnetcdf.c $(CPPINCLUDES) $(CFLAGS) $(LDFLAGS) -L$(PNETCDF)/$(PNETCDFLIBLOC) -lpnetcdf  -o pnetcdf.out > pnetcdf.log 2>&1; \
+	   if [ $$? -eq 0 ] ; then \
+	       echo "$(CC) can compile test PnetCDF C program."; \
+	   else \
+	       echo "*********************************************************"; \
+	       echo "ERROR: Test PnetCDF C program could not be compiled by $(CC)."; \
+	       echo "Please ensure you have a working PnetCDF library installed."; \
+	       echo ""; \
+	       echo "The following compilation command failed with errors:" ; \
+	       echo "$(CC) pnetcdf.c $(CPPINCLUDES) $(CFLAGS) $(LDFLAGS) -L$(PNETCDF)/$(PNETCDFLIBLOC) -lpnetcdf -o pnetcdf.out"; \
+	       echo ""; \
+	       echo "Test program pnetcdf.c and output pnetcdf.log have been left"; \
+	       echo "in the top-level MPAS directory for further debugging"; \
+	       echo "*********************************************************"; \
+	       rm -f pnetcdf.out; exit 1; \
+	   fi )
+
+	@rm -f pnetcdf.c pnetcdf.out pnetcdf.log
+else
+	@echo "*********************************************************"; \
+	 echo "ERROR: The PNETCDF environment variable isn't set."; \
+	 echo "Please set this variable to where PnetCDF is installed."; \
+	 echo "*********************************************************"; \
+	 exit 1
+endif
+
+
 ifneq "$(PIO)" ""
-MAIN_DEPS = rebuild_check openmp_test openacc_test pio_test mpi_f08_test
+MAIN_DEPS = rebuild_check openmp_test openacc_test pnetcdf_test pio_test mpi_f08_test
 override CPPFLAGS += "-DMPAS_PIO_SUPPORT"
 else
-MAIN_DEPS = rebuild_check openmp_test openacc_test mpi_f08_test
+MAIN_DEPS = rebuild_check openmp_test openacc_test pnetcdf_test mpi_f08_test
 IO_MESSAGE = "Using the SMIOL library."
 override CPPFLAGS += "-DMPAS_SMIOL_SUPPORT"
 endif