Fix Singlenozzle Standby issues (#21759)

Fixes #21758

Co-authored-by: Scott Lahteine <github@thinkyhead.com>

Marlin/src/inc/Conditionals_LCD.h

 #endif
 
 /**
+ * Disable unused SINGLENOZZLE sub-options
+ */
+#if DISABLED(SINGLENOZZLE)
+  #undef SINGLENOZZLE_STANDBY_TEMP
+#endif
+#if !BOTH(HAS_FAN, SINGLENOZZLE)
+  #undef SINGLENOZZLE_STANDBY_FAN
+#endif
+
+/**
  * DISTINCT_E_FACTORS affects how some E factors are accessed
  */
 #if ENABLED(DISTINCT_E_FACTORS) && E_STEPPERS > 1

Marlin/src/lcd/menu/menu_temperature.cpp

 
   #if ENABLED(SINGLENOZZLE_STANDBY_TEMP)
     LOOP_S_L_N(e, 1, EXTRUDERS)
-      EDIT_ITEM_FAST_N(uint16_3, e, MSG_NOZZLE_STANDBY, &thermalManager.singlenozzle_temp[e], 0, thermalManager.hotend_max_target(0));
+      EDIT_ITEM_FAST_N(int3, e, MSG_NOZZLE_STANDBY, &thermalManager.singlenozzle_temp[e], 0, thermalManager.hotend_max_target(0));
   #endif
 
   //

Marlin/src/lcd/menu/menu_tune.cpp

 
   #if ENABLED(SINGLENOZZLE_STANDBY_TEMP)
     LOOP_S_L_N(e, 1, EXTRUDERS)
-      EDIT_ITEM_FAST_N(uint16_3, e, MSG_NOZZLE_STANDBY, &thermalManager.singlenozzle_temp[e], 0, thermalManager.hotend_max_target(0));
+      EDIT_ITEM_FAST_N(int3, e, MSG_NOZZLE_STANDBY, &thermalManager.singlenozzle_temp[e], 0, thermalManager.hotend_max_target(0));
   #endif
 
   //

Marlin/src/module/temperature.cpp

 
 #if ENABLED(SINGLENOZZLE_STANDBY_TEMP)
   celsius_t Temperature::singlenozzle_temp[EXTRUDERS];
-  #if HAS_FAN
+#endif
-    uint8_t Temperature::singlenozzle_fan_speed[EXTRUDERS];
+#if ENABLED(SINGLENOZZLE_STANDBY_FAN)
-  #endif
+  uint8_t Temperature::singlenozzle_fan_speed[EXTRUDERS];
 #endif
 
 #if ENABLED(PROBING_HEATERS_OFF)
 
 #endif // PROBING_HEATERS_OFF
 
-#if ENABLED(SINGLENOZZLE_STANDBY_TEMP)
+#if EITHER(SINGLENOZZLE_STANDBY_TEMP, SINGLENOZZLE_STANDBY_FAN)
 
   void Temperature::singlenozzle_change(const uint8_t old_tool, const uint8_t new_tool) {
-    #if HAS_FAN
+    #if ENABLED(SINGLENOZZLE_STANDBY_FAN)
       singlenozzle_fan_speed[old_tool] = fan_speed[0];
       fan_speed[0] = singlenozzle_fan_speed[new_tool];
     #endif
-    singlenozzle_temp[old_tool] = temp_hotend[0].target;
+    #if ENABLED(SINGLENOZZLE_STANDBY_TEMP)
-    if (singlenozzle_temp[new_tool] && singlenozzle_temp[new_tool] != singlenozzle_temp[old_tool]) {
+      singlenozzle_temp[old_tool] = temp_hotend[0].target;
-      setTargetHotend(singlenozzle_temp[new_tool], 0);
+      if (singlenozzle_temp[new_tool] && singlenozzle_temp[new_tool] != singlenozzle_temp[old_tool]) {
-      TERN_(AUTOTEMP, planner.autotemp_update());
+        setTargetHotend(singlenozzle_temp[new_tool], 0);
-      TERN_(HAS_STATUS_MESSAGE, set_heating_message(0));
+        TERN_(AUTOTEMP, planner.autotemp_update());
-      (void)wait_for_hotend(0, false);  // Wait for heating or cooling
+        TERN_(HAS_STATUS_MESSAGE, set_heating_message(0));
-    }
+        (void)wait_for_hotend(0, false);  // Wait for heating or cooling
+      }
+    #endif
   }
 
 #endif

Marlin/src/module/temperature.h

     static inline bool hotEnoughToExtrude(const uint8_t e) { return !tooColdToExtrude(e); }
     static inline bool targetHotEnoughToExtrude(const uint8_t e) { return !targetTooColdToExtrude(e); }
 
-    #if ENABLED(SINGLENOZZLE_STANDBY_FAN)
+    #if EITHER(SINGLENOZZLE_STANDBY_TEMP, SINGLENOZZLE_STANDBY_FAN)
-      static celsius_t singlenozzle_temp[EXTRUDERS];
+      #if ENABLED(SINGLENOZZLE_STANDBY_TEMP)
-      #if HAS_FAN
+        static celsius_t singlenozzle_temp[EXTRUDERS];
+      #endif
+      #if ENABLED(SINGLENOZZLE_STANDBY_FAN)
         static uint8_t singlenozzle_fan_speed[EXTRUDERS];
       #endif
       static void singlenozzle_change(const uint8_t old_tool, const uint8_t new_tool);

Marlin/src/module/tool_change.cpp

       const bool should_move = safe_to_move && !no_move && IsRunning();
       if (should_move) {
 
-        TERN_(SINGLENOZZLE_STANDBY_TEMP, thermalManager.singlenozzle_change(old_tool, new_tool));
+        #if EITHER(SINGLENOZZLE_STANDBY_TEMP, SINGLENOZZLE_STANDBY_FAN)
+          thermalManager.singlenozzle_change(old_tool, new_tool);
+        #endif
 
         #if ENABLED(TOOLCHANGE_FILAMENT_SWAP)
           if (should_swap && !too_cold) {