Implement some functions on Linux

.gitignore

Cargo.lock

Cargo.toml

crt0/Cargo.toml

crt0/src/lib.rs

fcntl/Cargo.toml

fcntl/src/lib.rs

fcntl/src/linux.rs

fcntl/src/redox.rs

include/sys/types.h

platform/Cargo.toml

platform/src/lib.rs

platform/src/linux/mod.rs

platform/src/redox/mod.rs

platform/src/types.rs

rust-toolchain

src/lib.rs

test.sh

tests/.gitignore

tests/Makefile