remove custom netcdf find function

[jedwards4b]

Remove the custom code used to find netcdf and use pkg_config instead.

[haampie]

I've used this PR plus the following diff

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 330c0fb..0404289 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -76,19 +76,19 @@ foreach (SRC_FILE IN LISTS CPRNC_GenF90_SRCS)
 endforeach ()
 
 #===== NetCDF =====
-pkg_check_modules(NetCDF REQUIRED netcdf)
+pkg_check_modules(NetCDF REQUIRED IMPORTED_TARGET netcdf)
 
 #===== NetCDF-Fortran =====
-pkg_check_modules(NetCDF_Fortran REQUIRED netcdf-fortran)
+pkg_check_modules(NetCDF_Fortran REQUIRED IMPORTED_TARGET netcdf-fortran)
 add_executable (cprnc ${CPRNC_Fortran_SRCS} ${CPRNC_GenF90_SRCS})
-target_include_directories(cprnc PUBLIC ${CMAKE_CURRENT_SOURCE_DIR} ${NetCDF_Fortran_INCLUDE_DIRS})
+target_include_directories(cprnc PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 
 add_dependencies (cprnc genf90)
 
 # Always use -fPIC
 set_property(TARGET cprnc PROPERTY POSITION_INDEPENDENT_CODE ON)
 target_link_libraries (cprnc
-    PUBLIC ${NetCDF_Fortran_LIBRARIES} ${NetCDF_LIBRARIES})
+    PUBLIC PkgConfig::NetCDF_Fortran PkgConfig::NetCDF)
 
 # We do not want cprnc injecting ctests into parent projects
 if (CPRNC_STANDALONE)

and verified that CMAKE_INSTALL_RPATH_USE_LINK_PATH works.

The upside of IMPORTED_TARGET is you need target_link_libraries only once, and it accounts for all cflags / ldflags.

[jedwards4b]

I also ran the cime test_self_build_cprnc:(test_sys_cime_case.TestCimeCase) ... ok

[jgfouca]

This is a great change, thanks!

[climbfuji]

Does this work with static libraries?

https://github.com/NOAA-EMC/CMakeModules/blob/9b7652c75b40d9cbb40e52b824f8c0a423922757/Modules/FindNetCDF.cmake#L232