Bump libc and sdl2 versions to 0.2 and 0.16 respectively
Bump libc and sdl2 versions to 0.2 and 0.16 respectively

andelf/rust-sdl2_gfx,Cobrand/rust-sdl2,Cobrand/rust-sdl2,vadixidav/rust-sdl2,Cobrand/rust-sdl2,AngryLawyer/rust-sdl2,Rust-SDL2/rust-sdl2,Rust-SDL2/rust-sdl2,Rust-SDL2/rust-sdl2