Added some DragonFly-only constants.
Added some DragonFly-only constants.

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