Update gengen.sh
Update gengen.sh

Many options were missing. (Apparently there is not even a test for
gengen.sh inside Halide.)


Former-commit-id: cf7c72b39b3aa915433c7e0986700005ddfb7153
Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide