- startup.c: include wl_backend.h when USE_WAYLAND_BACKEND is defined;
select wl_backend when WMAKER_USE_WAYLAND env var is set, otherwise
fall back to x11_backend (no-op for non-Wayland builds)
- tests/smoke-test.sh renamed to tests/x11-smoke-test.sh (X11-only path)
- tests/wl-smoke-test.sh: new Wayland smoke test; currently verifies
wl_backend symbol presence and wlroots linkage; headless compositor
tests will be added as vtable slots are implemented
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>