Add O_DIRECT

[tmancill]

Is there a reason that O_DIRECT couldn't be added to OpenFlags? Would you accept a PR for it?

For my specific use case, I'm getting some Java code ready to run on both x86-64 and aarch64, and it's inconvenient that the (currently hard-coded constant) for O_DIRECT on x86-64 maps to the value of O_DIRECTORY on aarch64.

[headius]

Do it! Any flag can be added because all flags can be queried to know whether they are defined on the current platform, and when we regenerate for the other platforms we will pick it up if it exists!

[headius]

regenerate for the other platforms

Or modify by hand, carefully. 😀

[almson]

@tmancill Also O_LARGEFILE and everything else that's in current fcntl.h so that we don't have to ask again 🥺

[headius]

Yeah, add anything standard you see and we'll get them generated and released.