Silence some warnings by using feature(libc).
Silence some warnings by using feature(libc).

Rust-SDL2/rust-sdl2,Cobrand/rust-sdl2,Rust-SDL2/rust-sdl2,AngryLawyer/rust-sdl2,beni55/rust-sdl2_ttf,andelf/rust-sdl2_ttf,vadixidav/rust-sdl2,Cobrand/rust-sdl2,Machtan/rust-sdl2_ttf,VoxWave/rust-sdl2_ttf,Rust-SDL2/rust-sdl2,Cobrand/rust-sdl2