Auto merge of #560 - Mic92:fchown, r=alexcrichton
Auto merge of #560 - Mic92:fchown, r=alexcrichton

Add fchown

cactorium/libc,mneumann/libc,rust-lang/libc,rust-lang/libc,anatol/libc,anatol/libc,anatol/libc,rust-lang-nursery/libc,cactorium/libc,mneumann/libc,rust-lang-nursery/libc,mneumann/libc,rust-lang/libc,cactorium/libc,rust-lang-nursery/libc