guard XWayland startup path behind USE_XWAYLAND: skip XOpenDisplay and pump thread in pure Wayland build

src/backend/wayland/wl_backend.c

@@ -965,6 +965,7 @@ wl_display_open(const char *name)
     /* XWayland is lazy — it starts when the first X11 client connects.
      * No need to wait for it at startup. Mark as ready so the rest of
      * init proceeds without blocking. */
+#ifdef USE_XWAYLAND
     if (wl_state.xwayland) {
         wwarning("wl_backend: XWayland configured (eager mode) — ready at startup");
         wl_state.xwayland_ready = true;
@@ -990,6 +991,7 @@ wl_display_open(const char *name)
             wwarning("wl_backend: XWayland ready but XOpenDisplay failed — pure Wayland mode");
         }
     }
+#endif
 
     return NULL; /* dpy=NULL so WM core skips Xlib calls */
 }