static int last_mousemove_x = 0;
static int last_mousemove_y = 0;
+/* Define GET_WHEEL_DELTA_WPARAM macro if system headers don't. */
+#ifndef GET_WHEEL_DELTA_WPARAM
+#define GET_WHEEL_DELTA_WPARAM(wparam) ((short)HIWORD (wparam))
+#endif
+
/* Non-zero means that a HELP_EVENT has been generated since Emacs
start. */