Eu estou tentando compilar um projeto CMake que usa

<code>set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} "-Wall -std=gnu++0x")
</code>

no arquivo CMakeLists.txt no MacOS X Lion. Eu instalei o XCode 4.2.1. mas o compilador falha com isso:

<code>cd something/src/lib && /usr/bin/c++   -Dlib_ginacra_EXPORTS -Wall -std=gnu++0x -fPIC   -o CMakeFiles/lib_ginacra.dir/utilities.cpp.o -c something/src/lib/utilities.cpp
cc1plus: error: unrecognized command line option "-std=gnu++0x"
</code>

A versão do compilador é:

<code>c++ --version
i686-apple-darwin11-llvm-g++-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.1.00)
</code>