Auto merge of #2683 - deantvv:wasi-langinfo, r=Amanieu
Auto merge of #2683 - deantvv:wasi-langinfo, r=Amanieu

wasi add langinfo.h

Reference: [langinfo.h](https://github.com/WebAssembly/wasi-libc/blob/659ff414560721b1660a19685110e484a081c3d4/libc-top-half/musl/include/langinfo.h)

rust-lang/libc,rust-lang/libc,rust-lang/libc