rename MACOS9 to MAC68K to avoid confusion with modern macOS

win/tty/wintty.c

@@ -20,7 +20,7 @@
 /* leave this undefined; it produces bad screen output with rxvt-unicode */
 /*#define DECgraphicsOptimization*/
 
-#ifdef MACOS9
+#ifdef MAC68K
 #define MICRO /* The Mac is a MICRO only for this file, not in general! */
 #ifdef THINK_C
 extern void msmsg(const char *, ...);
@@ -143,7 +143,7 @@ struct window_procs tty_procs = {
     tty_getlin, tty_get_ext_cmd, tty_number_pad, tty_delay_output,
 #ifdef CHANGE_COLOR /* the Mac uses a palette device */
     tty_change_color,
-#ifdef MACOS9
+#ifdef MAC68K
     tty_change_background, set_tty_font_name,
 #endif
     tty_get_color_string,