Removed unused libc imports in termios.
Removed unused libc imports in termios.

carllerche/nix-rust,MarkusJais/nix-rust,xd009642/nix,Susurrus/nix,carllerche/nix-rust,MarkusJais/nix-rust,berkowski/nix,Susurrus/nix,kamalmarhubi/nix-rust,kamalmarhubi/nix-rust,geofft/nix-rust,xd009642/nix,nix-rust/nix,nix-rust/nix,Susurrus/nix,MarkusJais/nix-rust,geofft/nix-rust,xd009642/nix,asomers/nix,berkowski/nix,asomers/nix,carllerche/nix-rust,berkowski/nix,kamalmarhubi/nix-rust,geofft/nix-rust