MPI not detected on `gadi` by cmake

[manodeep]

Following the instructions to install and running build.sh results in an error about detecting the MPI package (even though that module is loaded by build.sh).

[~/temp/libaccessom2 @gadi04] ./build.sh 
build.sh: Set up environment on gadi.nci.org.au
build.sh: executing cmake with $PATH set to: /apps/openmpi/wrapper/fortran:/apps/openmpi/wrapper:/apps/openmpi/4.0.2/bin:/apps/netcdf/4.7.4/bin:/apps/intel-ct/wrapper:/apps/intel-ct/2019.5.281/compiler/bin:/home/593/ms2335/.vscode-server/cli/servers/Stable-138f619c86f1199955d53b4166bef66ef252935c/server/bin/remote-cli:/home/593/ms2335/codes/climate_models/mkmf/bin:/home/593/ms2335/.local/bin:/home/593/ms2335/bin:/opt/pbs/default/bin:/opt/nci/bin:/opt/bin:/opt/Modules/v4.3.0/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin

-- The Fortran compiler identification is Intel 19.0.5.20190815
-- Detecting Fortran compiler ABI info
-- Detecting Fortran compiler ABI info - done
-- Check for working Fortran compiler: /apps/intel-ct/wrapper/ifort - skipped
---- PROJECT_VERSION: '2.0.202212'
---- FQDN: gadi-login-04.gadi.nci.org.au
---- NUMBER_OF_LOGICAL_CORES: 48
-- Could NOT find MPI_Fortran (missing: MPI_Fortran_F77_HEADER_DIR MPI_Fortran_MODULE_DIR) (found version "3.1")
CMake Error at /half-root/usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
  Could NOT find MPI (missing: MPI_Fortran_FOUND) (found version "3.1")
Call Stack (most recent call first):
  /half-root/usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:600 (_FPHSA_FAILURE_MESSAGE)
  /half-root/usr/share/cmake/Modules/FindMPI.cmake:1837 (find_package_handle_standard_args)
  CMakeLists.txt:34 (find_package)


-- Configuring incomplete, errors occurred!

Based on previous discussions, this is likely a known issue but the fix for MPI is to include the CMAKE_PREFIX_PATH into the cmake command:

-cmake -S ${PROJDIR} -B ${BUILDDIR} && \
+cmake -S ${PROJDIR} -B ${BUILDDIR} -DCMAKE_PREFIX_PATH=$OMPI_ROOT/include/Intel && \

With this patch, the MPI compilers are found correctly

[~/temp/libaccessom2 @gadi04] git diff
diff --git a/build.sh b/build.sh
index 78fa4e4..1a3c5d7 100755
--- a/build.sh
+++ b/build.sh
@@ -18,5 +18,5 @@ echo -e "${PROGNAME}: executing cmake with \$PATH set to: $PATH\n"
 
 rm -rf ${BUILDDIR} && \
 mkdir -p ${BUILDDIR} && \
-cmake -S ${PROJDIR} -B ${BUILDDIR} && \
+cmake -S ${PROJDIR} -B ${BUILDDIR} -DCMAKE_PREFIX_PATH=$OMPI_ROOT/include/Intel && \
 cmake --build ${BUILDDIR} --verbose
[~/temp/libaccessom2 @gadi04] ./build.sh 
build.sh: Set up environment on gadi.nci.org.au
build.sh: executing cmake with $PATH set to: /apps/openmpi/wrapper/fortran:/apps/openmpi/wrapper:/apps/openmpi/4.0.2/bin:/apps/netcdf/4.7.4/bin:/apps/intel-ct/wrapper:/apps/intel-ct/2019.5.281/compiler/bin:/home/593/ms2335/.vscode-server/cli/servers/Stable-138f619c86f1199955d53b4166bef66ef252935c/server/bin/remote-cli:/home/593/ms2335/codes/climate_models/mkmf/bin:/home/593/ms2335/.local/bin:/home/593/ms2335/bin:/opt/pbs/default/bin:/opt/nci/bin:/opt/bin:/opt/Modules/v4.3.0/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin

-- The Fortran compiler identification is Intel 19.0.5.20190815
-- Detecting Fortran compiler ABI info
-- Detecting Fortran compiler ABI info - done
-- Check for working Fortran compiler: /apps/intel-ct/wrapper/ifort - skipped
---- PROJECT_VERSION: '2.0.202212'
---- FQDN: gadi-login-04.gadi.nci.org.au
---- NUMBER_OF_LOGICAL_CORES: 48
-- Found MPI_Fortran: /apps/openmpi/4.0.2/lib/Intel/libmpi_usempif08.so (found version "3.1") 
-- Found MPI: TRUE (found version "3.1")  
---- MPI_Fortran_COMPILER: /apps/openmpi/4.0.2/bin/mpif90
---- CMAKE_Fortran_COMPILER: /apps/openmpi/4.0.2/bin/mpif90

(The build then fails because it can't find the other dependencies but that's a separate issue)

[manodeep]

This change is not required for the COSIMA/libaccessom2 package.

[aidanheerdegen]

We're supporting building using the spack package.

I prefer we update the install instructions to reflect this.

The non-standard include paths on gadi are part of the gadi spack config, so the problem is solved globally and doesn't require patching every build script.