Command line warning D9002: ignoring unknown option '-std=c++11'

In my CMakeList.txt file, I have the following in order to add c++11 supports:

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

This works fine under Mac with Xcode. However, I get the following warning message from Visual Studio. Any idea?

Command line warning D9002: ignoring unknown option '-std=c++0x'

Other than the compile warning, the program gets compile and run with no problem. I am using VS2013. If I remove that single "set flag" line, the warning goes away.