Fix tutorial build under CMake for Linux. Not sure if this breaks the build on OSX.
Fix tutorial build under CMake for Linux. Not sure if this breaks the
build on OSX.


Former-commit-id: 793a6c1cfbf8281718165bfa4c51c0de09637979
Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide