Make sure OLD_CURSOR code is only for SUNDISPLAY. (#279)

This is work in progress on Interlisp/medley#84.

src/dspsubrs.c

@@ -99,7 +99,7 @@ void DSP_Cursor(LispPTR *args, int argnum)
   extern int ScreenLocked;
   extern DLword *EmCursorX68K, *EmCursorY68K;
   extern int LastCursorX, LastCursorY;
-#if !defined(OLD_CURSOR)
+#if defined(SUNDISPLAY) && !defined(OLD_CURSOR)
   static int Init = T;
 #endif
 

src/keyevent.c

@@ -173,6 +173,8 @@ typedef struct {
 
 /*  EmXXXX68K are already swapped, no need for GETWORD */
 
+
+#ifdef SUNDISPLAY
 #ifdef OLD_CURSOR
 #define TrackCursor(cx, cy)                          \
   {                                                  \
@@ -190,6 +192,7 @@ typedef struct {
     *EmCursorY68K = cy;                              \
   }
 #endif /* OLD_CURSOR */
+#endif /* SUNDISPLAY */
 
 /* commented out is some code that would also clobber
         Irq_Stk_Check & Irq_Stk_End to force