Auto merge of #1200 - alecmocatta:master, r=alexcrichton

add FIO* for FreeBSD and NetBSD

Calculated [here](https://repl.it/repls/PaltryTroubledMonitors) from FreeBSD [source](https://github.com/freebsd/freebsd/blob/9867e6d8fe1cac34121e5f2df9357363f5659617/sys/sys/filio.h).

Calculated [here](https://repl.it/repls/ProfitableImpracticalComputeranimation) from NetBSD [source](https://github.com/NetBSD/src/blob/64b8a48e1288eb3902ed73113d157af50b2ec596/sys/sys/filio.h).

Some of these are likely identical across all BSDs – if this can be confirmed they could be elevated to `unix/bsd/mod.rs` alongside `FIOCLEX` and `FIONBIO`.