xwayland: Fix out of bounds write
Detected using ASAN, declaration of the type is: typedef union xcb_client_message_data_t { uint8_t data8[20]; uint16_t data16[10]; uint32_t data32[5]; } xcb_client_message_data_t;
Detected using ASAN, declaration of the type is: typedef union xcb_client_message_data_t { uint8_t data8[20]; uint16_t data16[10]; uint32_t data32[5]; } xcb_client_message_data_t;
mentioned in commit 715cc6d2