message: adds MPI include dirs to the default includes
diff: @@ -15,6 +15,9 @@ function(ginkgo_default_includes name)
  $<BUILD_INTERFACE:${HWLOC_INCLUDE_DIRS}>
  )
  endif()
  + if(GINKGO_BUILD_MPI)
  + target_include_directories("${name}" PUBLIC ${MPI_CXX_INCLUDE_DIRS})
  + endif()
  endfunction()
  function(ginkgo_compile_features name)
  