--- a/parallel/CMakeLists.txt	2020-03-24 23:00:09.873941559 +0100
+++ b/parallel/CMakeLists.txt.patched	2020-03-24 23:11:41.287296340 +0100
@@ -3,7 +3,8 @@
   # Maybe dune-common should export them?
   add_definitions(-DENABLE_MPI=1 -DMPICH_SKIP_MPICXX -DMPIPP_H)
   include_directories("${MPI_DUNE_INCLUDE_PATH}")
-  set_property(DIRECTORY APPEND PROPERTY COMPILE_OPTIONS "${MPI_DUNE_COMPILE_FLAGS}")
+  separate_arguments(MPI_DUNE_COMPILE_FLAGS UNIX_COMMAND "${MPI_DUNE_COMPILE_FLAGS}")
+  set_property(DIRECTORY APPEND PROPERTY COMPILE_OPTIONS ${MPI_DUNE_COMPILE_FLAGS})
  ug_add_dim_libs(parallel OBJECT initparallel.cc) # OBJECT_DIM_LIBS ddd dddif)
 endif()