Merge pull request #480 from kurylo/fix/2016-09-29-cmake-warning

Fix cmake warnings on new cmake versions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ec2e58f..e9b44d5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,6 +7,9 @@
 ENDIF(BIICODE)

 cmake_minimum_required(VERSION 2.6 FATAL_ERROR)

 cmake_policy(VERSION 2.6)

+if(POLICY CMP0063)
+	cmake_policy(SET CMP0063 OLD)
+endif()
 

 project(tinyxml2)

 include(GNUInstallDirs)