unable to use some c++11 features in generic project

I've compiled QtCreator after https://codereview.qt-project.org/#change,62536 but autocompletion for say std::tuple still doesn't work in my Makefile-based project. This is caused by __cplusplus not being defined in Creator's parser. I've added "#define __cplusplus 201103" to myproject.config, and got it working. Shouldn't it be done automatically?