Add binding for mremap.
Add binding for mremap.

rust-lang-nursery/libc,zethra/libc,mneumann/libc,zethra/libc,superriva/libc,superriva/libc,philippkeller/libc,anatol/libc,mneumann/libc,philippkeller/libc,cactorium/libc,rust-lang/libc,superriva/libc,philippkeller/libc,cactorium/libc,zethra/libc,rust-lang-nursery/libc,rust-lang-nursery/libc,mneumann/libc,rust-lang/libc,anatol/libc,anatol/libc,cactorium/libc,rust-lang/libc