Qt Creator使用位于另一个地方的另一个GCC版本

I installed a gcc 4.8.0 in the /opt folder. I put in my PATH, so when i do a gcc/g++ -v it returns to me the 4.8.0 version. But when i go to the QT Creator and compile my program with the c++11 code (implemented in 4.3 > ) it don't compile. So i put a -v option in the QMAKE_CXXFLAGS flag. So i get:I installed a gcc 4.8.0 in the /opt folder. I p