diff --git a/CMakeLists.txt b/CMakeLists.txt
index ef39662a0fa6d3c4d110949cd7bd1fb5de519f1d..68a9d62a2318075197faaf92c9a1a029bb22a741 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,6 +4,10 @@ option(CM_ALL_VTK_OUTPUT "VTK output routine" OFF)
 option(CM_ALL_VORONOI "Voronoi-based loadbalancing scheme (requires Voro++)" OFF)
 option(CM_ALL_FORTRAN "VTK output routine" OFF)
 
+# leading and trailing whitespace should be silently ignored
+# thanks to an old FindMPI script
+cmake_policy(SET CMP0004 OLD)
+
 enable_language(CXX)
 
 if (CM_ALL_FORTRAN)