Implement sys/file.h

src/platform/src/linux/mod.rs

src/platform/src/redox/mod.rs

src/platform/src/types.rs

src/sys_file/Cargo.toml

src/sys_file/build.rs

src/sys_file/cbindgen.toml

src/sys_file/src/lib.rs

src/sys_ioctl/cbindgen.toml