set language standard variables in example project

CMakeLists.txt

@@ -11,6 +11,11 @@ project (CotireExample)
 
 set (CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/CMake")
 
+if (NOT CMAKE_VERSION VERSION_LESS "3.1.0")
+	set (CMAKE_CXX_STANDARD "98")
+	set (CMAKE_CXX_EXTENSIONS OFF)
+endif()
+
 include(cotire)
 
 add_subdirectory(src)