Reorganize

Cargo.toml

src/fcntl/Cargo.toml

src/fcntl/build.rs

src/fcntl/cbindgen.toml

src/fcntl/src/lib.rs

src/fcntl/src/linux.rs

src/fcntl/src/redox.rs

src/stdio/Cargo.toml

src/stdio/build.rs

src/stdio/cbindgen.toml

src/stdio/src/lib.rs

src/stdio/src/printf.rs

src/stdlib/Cargo.toml

src/stdlib/build.rs

src/stdlib/cbindgen.toml

src/stdlib/src/lib.rs

src/string/Cargo.toml

src/string/build.rs

src/string/cbindgen.toml

src/string/src/lib.rs