Use private mapping from provided shm_pool buffer

[Caellian]

Using MAP_SHARED causes a crash on some compositors/systems as shown by #1824. According to WL docs:

From version 7 onwards, the fd must be mapped with MAP_PRIVATE by the recipient, as MAP_SHARED may fail.

We don't need a MAP_SHARED as the provided buffer will be used exclusively by conky and not shared with other processes.

This PR addresses that and closes #1824.

Testing

• Tested private mapping in another Wayland client and it worked with hyprland.

[netlify]

✅ Deploy Preview for conkyweb canceled.

Name	Link
🔨 Latest commit	a576c2c
🔍 Latest deploy log	https://app.netlify.com/sites/conkyweb/deploys/66310e808e6cc10007ef11cc

[stacyharper]

This cause a problem, at least on Sway last release (1.10). I just display nothing.

Also the doc mention this:

From version 7 onwards, the fd must be mapped with MAP_PRIVATE by the recipient, as MAP_SHARED may fail.

But on the wl_keyboard::keymap part. Are we sure this is really required here?

Reverting this one, plus #2103, make out_to_wayland = true to works now.

edit:

Honestly I don't see how this could works. We are sharing a buffer with the compositor. If we make this private, the compositor does not receive update on this buffer. So It just display a blank one.

edit2:

I just tried this on Hyprland, and we also need to revert this here.