Auto merge of #2072 - smklein:solarish_directory, r=Amanieu
Auto merge of #2072 - smklein:solarish_directory, r=Amanieu

Add O_DIRECTORY to solarish

FYI `@pfmooney` . I was trying to port [nix](https://crates.io/crates/nix) to illumos, and noticed this in the illumos-gate [headers](https://github.com/illumos/illumos-gate/blob/221e47fb90c5fcfe7add9a33f6c915ee5253ece9/usr/src/uts/common/sys/fcntl.h), but not in libc.

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