Reduce warnings

src/c_str.rs

src/header/arpa_inet/mod.rs

src/header/fnmatch/mod.rs

src/header/setjmp/mod.rs

src/header/signal/mod.rs

src/header/stdio/mod.rs

src/header/stdlib/mod.rs

src/header/strings/mod.rs

src/header/sys_resource/mod.rs

src/header/sys_socket/mod.rs

src/header/sys_un/mod.rs

src/header/sys_wait/mod.rs

src/header/time/constants.rs

src/header/time/strftime.rs

src/header/unistd/mod.rs

src/header/wchar/mod.rs

src/header/wchar/utf8.rs

src/lib.rs

src/platform/linux/mod.rs

src/platform/pal/mod.rs