@darkhorse raises an interesting point–it may no longer be needed. Check out this comment on a related GitHub issue: Can't install waybar-hyprland on Arch · Issue #2177 · Alexays/Waybar · GitHub
First and foremost, this bug is closed because the problem has been fixed upstream, and you don’t need to do anything. In fact, you probably shouldn’t use the
waybar-hyprlandAUR package at all because AFIK mainline waybar now has all the hyprland support it used to patch in. Just install the waybar package and it’ll do the thing.Just for your reference on AUR usage, my suggestion isn’t to put on the command line, it’s to edit in the PKGBUILD. After you ran that yay command once (whether the build succeeded or failed), it would leave a directory
/home/$USER/.cache/yay/waybar-hyprlandcontaining all the sources and a file named PKGBUILD that describes to arch’s build system how to make the package. If you open that file up in a text editor, you can make customizations to the build/install process, and my suggestion was to drop that sed command into the section/function marked build(). What that would do is edit one of the waybar source files before the build with sed (which is itself a text editor; it edits text by structured command instead of on screen) to insert some includes that used to be implicitly pulled in and aren’t anymore.