Enable c++11 in cmake

CMakeLists.txt

@@ -64,6 +64,7 @@ target_link_libraries(randomx
   PRIVATE
     ${CMAKE_THREAD_LIBS_INIT})
 set_property(TARGET randomx PROPERTY POSITION_INDEPENDENT_CODE ON)
+set_property(TARGET randomx PROPERTY CXX_STANDARD 11)
 
 # cheat because cmake and ccache hate each other
 set_property(SOURCE src/jit_compiler_x86_static.S PROPERTY LANGUAGE C)