Fix how FindNetCDF finds MPI (#44)

Fix FindNetCDF with MPI

Remove COMPONENTS from FindMPI. If blank it search for all enabled languages. Otherwise, for a project without C enabled it would fail to fail to find MPI C.

Modules/FindNetCDF.cmake

@@ -178,11 +178,14 @@ if( NOT _val MATCHES "^(yes|no)$" )
 endif()
 if( _val MATCHES "^(yes)$" )
   set(NetCDF_PARALLEL TRUE CACHE STRING "NetCDF has parallel IO capability via pnetcdf or hdf5." FORCE)
-  find_package(MPI REQUIRED COMPONENTS C)
 else()
   set(NetCDF_PARALLEL FALSE CACHE STRING "NetCDF has no parallel IO capability." FORCE)
 endif()
 
+if(NetCDF_PARALLEL)
+  find_package(MPI REQUIRED)
+endif()
+
 ## Find libraries for each component
 set( NetCDF_LIBRARIES )
 foreach( _comp IN LISTS _search_components )
@@ -242,11 +245,9 @@ foreach( _comp IN LISTS _search_components )
         INTERFACE_LINK_LIBRARIES ${NetCDF_${_comp}_LIBRARIES} )
       if( NOT _comp MATCHES "^(C)$" )
         target_link_libraries(NetCDF::NetCDF_${_comp} INTERFACE NetCDF::NetCDF_C)
-      else()
-        # Link NetCDF C lib to MPI (which transitively applies to other components)
-        if(NetCDF_PARALLEL)
-          target_link_libraries(NetCDF::NetCDF_C INTERFACE MPI::MPI_C)
-        endif()
+      endif()
+      if(MPI_${_comp}_FOUND)
+        target_link_libraries(NetCDF::NetCDF_${_comp} INTERFACE MPI::MPI_${_comp})
       endif()
     endif()
   endif()