This pull request is a "cleanup" of the Wayland code, a.k.a. deleting the nearly ten thousand lines of code needed to support Wayland. The basis for dropping Wayland support is explained, "wayland support is unmaintained, and heavily depends on boost."
The code was merged, so Wayland support is in fact gone just ahead of the Kodi 17 release. Another developer though is hoping to clean-up the Wayland support and get it eventually merged back into Kodi. In place of the Boost library use would be proper C++11 code. Kodi has been working to remove their Boost library usage and yesterday succeeded in that task.
Judging from that pull request thread, there certainly are upstream members interested in getting the Wayland support into good shape, so hopefully it will return in the not too distant future. The Wayland code was largely maintained since it was added to XBMC two years ago. One of the repositories where at least for now the Kodi Wayland support is being worked on is here.