The x11-base/wayland ebuild, which builds only the wayland libs, includes all the dependencies for the wayland-demos. Needed are only dev-libs/libffi and dev-libs/expat. Reproducible: Always
Created attachment 278005 [details, diff] ebuild patch Patch for the ebuild. Removed xorg-2 class, changed the description, fixed the dependencies, and added an USE-flag for optional static lib build (I've seen this flag in some ebuilds so I added it).
Thanks, fixed.