build: Fix tests not running
common/flags: Update to latest upstream
build: Fix if build_root.path is null
README: Add a link to zelbar-river
data: Remove pointer arg in render()
This was not needed, remove the need for @ptrCast().
Lot of things changed (yes it should have been made in multiple commit):
* Removed scale for now, it was really buggy
* Bar: Move everything that was related to wayland to Backend.zig.
* Backend: Move the creation, configuration and rendering of the
surface in Surface.send_frame().
* Add some doc comments
Backend: Cleanup global interfaces versions
Backend: Remove Seat name
No need to allocate memory for something we don't use.
README: Add more buildings requirements
Render only in response to frame callbacks
Backend: Rewrite BufferPool
common: Update flags to latest upstream
ci: Update Wayland to 1.21
Backend: Use null data instead of undefined
Implement pointers events and action on click
Send <action> to STDOUT