Force C++11 for LLVM3.6
Force C++11 for LLVM3.6


Former-commit-id: 2eac9a5133931a111133f3b991d0307b26d1d2d6
darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide