Replace extra SOCK_ constants with libc versions
Replace extra SOCK_ constants with libc versions

Fixes #244

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