Add timer_* bindings

[Zapeth]

Feature request for adding bindings for the following POSIX timer functions to the crate:

• timer_create
• timer_delete
• timer_settime
• timer_gettime
• timer_getoverrun

See e.g. https://www.man7.org/linux/man-pages/man2/timer_create.2.html

[asomers]

That sounds like a good feature. Would you be willing to implement it?

[Zapeth]

I could try, but considering I only have rather limited experience with Rust I'm pretty sure other people that might be willing/interested to implement this feature would be better suited.

As a sidenote, I just checked if the libc crate provides these functions and it seems they have yet to be implemented as well (a PR draft exists but seems to be inactive for some time now), so that might be a necessary first step anyway before starting to work on it here.

[blt]

While it does appear that libc now has the relevant timer_* functions I think rust-lang/libc#2576 is a potential blocker. For what it's worth @asomers I need the timer functions and would be willing to provide an implementation. I'll put a PR together and get as far as possible with it.