Apple2: implement sleep using MONWAIT

Also publish detect_iigs(), set_iigs_speed() and get_iigs_speed(). Refactor to only store one ostype variable.

include/accelerator.h

@@ -304,6 +304,36 @@ unsigned char detect_turbomaster (void);
  * 0x01  : C64 Turbo Master cartridge present
  */
 
+unsigned char __fastcall__ set_iigs_speed (unsigned char speed);
+
+/* Set the speed of the Apple IIgs CPU.
+ *
+ * Possible values:
+ * SPEED_SLOW  : 1 Mhz mode
+ * SPEED_FAST  : Fast mode (2.8MHz or more, depending on the presence of
+ *               an accelerator)
+ *
+ * Any other value will be interpreted as SPEED_FAST.
+ */
+
+unsigned char get_iigs_speed (void);
+
+/* Get the speed of the Apple IIgs CPU.
+ *
+ * Possible return values:
+ * SPEED_SLOW  : 1 Mhz mode
+ * SPEED_FAST  : Fast mode (2.8MHz or more, depending on the presence of
+ *               an accelerator)
+ */
+
+unsigned char detect_iigs (void);
+
+/* Check whether we are running on an Apple IIgs.
+ *
+ * Possible return values:
+ * 0x00  : No
+ * 0x01  : Yes
+ */
+
 /* End of accelerator.h */
 #endif
-