File cxx11_compiler_flags.patch of Package rttr

Index: rttr-0.9.6/CMakeLists.txt
===================================================================
--- rttr-0.9.6.orig/CMakeLists.txt
+++ rttr-0.9.6/CMakeLists.txt
@@ -34,6 +34,7 @@
 cmake_minimum_required (VERSION 3.0)
 
 project ("rttr" LANGUAGES CXX)
+set(CMAKE_CXX_STANDARD 11)
 
 set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/CMake")