diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5bd4c35ed..a0d8f5eb4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,9 @@ cmake_minimum_required(VERSION 2.8.0 FATAL_ERROR)
 
 if(COMMAND cmake_policy)
     cmake_policy(SET CMP0003 NEW)
-    cmake_policy(SET CMP0020 NEW)
+    if(POLICY CMP0020)
+        cmake_policy(SET CMP0020 NEW)
+    endif(POLICY CMP0020)
     # added in cmake 3.0
     if(POLICY CMP0050)
         cmake_policy(SET CMP0050 OLD)