Update fft/funct.h to use variadic template for operator()
Update fft/funct.h to use variadic template for operator()


Former-commit-id: 167850bb3ebef3c4d126579cd692ce4f3fd36247
darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide