Support of Wayland

[nagayev]

Hi. Wayland have become the default graphics platform in Fedora, but you don't support it.
I can't compile my program without passing -lX11.

[dtschump]

Wayland should have a X11 compatibility layer. I've never tried if this is compatible with CImg or not.
BTW, the class CImgDisplay relies entirely on the X11 API. Rewriting it for another graphic library would require a lot of work.
If someone is interested to do so, please contact me (but it's unlikely I will do it myself).

[fractalaxy7]

It does work mostly fine with Wayland's compatibility layer for X11 (at least on Ubuntu 22.04), with the exception of rather annoying strobing occurring when resizing the window (I don't know if the strobing during resize was already a problem when using the original X11, I've not yet tried it).