[cmake,bugfix] Fixes adding ParMETIS flags

Previously, parmetis flags were not added as we used PARMETIS_COMPILE_FLAGS
which does not exist. This patch now sets the properties COMPILE_DEFINITIONS
and INCLUDE_DIRECTORIES for the targets and uses the correct values.

cmake/modules/AddParMETISFlags.cmake

@@ -10,10 +10,14 @@ function(add_dune_parmetis_flags _targets)
   if(PARMETIS_FOUND)
     foreach(_target ${_targets})
       target_link_libraries(${_target} ${PARMETIS_LIBRARY} ${METIS_LIBRARY})
-      GET_TARGET_PROPERTY(_props ${_target} COMPILE_FLAGS)
+      GET_TARGET_PROPERTY(_props ${_target} INCLUDE_DIRECTORIES)
       string(REPLACE "_props-NOTFOUND" "" _props "${_props}")
-      SET_TARGET_PROPERTIES(${_target} PROPERTIES COMPILE_FLAGS
-        "${_props} ${PARMETIS_COMPILE_FLAGS} -DENABLE_PARMETS=1")
+      SET_TARGET_PROPERTIES(${_target} PROPERTIES INCLUDE_DIRECTORIES
+        "${_props};${PARMETIS_INCLUDE_DIRS}")
+      GET_TARGET_PROPERTY(_props ${_target} COMPILE_DEFINITIONS)
+      string(REPLACE "_props-NOTFOUND" "" _props "${_props}")
+      SET_TARGET_PROPERTIES(${_target} PROPERTIES COMPILE_DEFINITIONS
+        "${_props};ENABLE_PARMETIS")
     endforeach(_target ${_targets})
     add_dune_mpi_flags(${_targets})
   endif(PARMETIS_FOUND)