[server] Add missing include

Fixes build with gcc 4.8.

BUG: 350058

src/wayland/fakeinput_interface.cpp

@@ -23,6 +23,7 @@ License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <QSizeF>
 
+#include <wayland-server.h>
 #include <wayland-fake-input-server-protocol.h>
 
 namespace KWayland