Make HAS_LCD_CONTRAST a boolean flag

Marlin/Conditionals.h

@@ -245,16 +245,10 @@
    * Default LCD contrast for dogm-like LCD displays
    */
   #if ENABLED(DOGLCD)
-    #if !defined(DEFAULT_LCD_CONTRAST)
+    #define HAS_LCD_CONTRAST (DISABLED(U8GLIB_ST7920) && DISABLED(U8GLIB_SSD1306) && DISABLED(U8GLIB_SH1106))
+    #if HAS_LCD_CONTRAST && !defined(DEFAULT_LCD_CONTRAST)
       #define DEFAULT_LCD_CONTRAST 32
     #endif
-    #define HAS_LCD_CONTRAST
-    #if ENABLED(U8GLIB_ST7920)
-      #undef HAS_LCD_CONTRAST
-    #endif
-    #if ENABLED(U8GLIB_SSD1306)
-      #undef HAS_LCD_CONTRAST
-    #endif
   #endif
 
 #else // CONFIGURATION_LCD

Marlin/Marlin_main.cpp

@@ -5624,7 +5624,7 @@ inline void gcode_M226() {
 
 #endif // CHDK || PHOTOGRAPH_PIN
 
-#if ENABLED(HAS_LCD_CONTRAST)
+#if HAS_LCD_CONTRAST
 
   /**
    * M250: Read and optionally set the LCD contrast
@@ -6975,7 +6975,7 @@ void process_next_command() {
           break;
       #endif // CHDK || PHOTOGRAPH_PIN
 
-      #if ENABLED(HAS_LCD_CONTRAST)
+      #if HAS_LCD_CONTRAST
         case 250: // M250  Set LCD contrast value: C<value> (value 0..63)
           gcode_M250();
           break;

Marlin/configuration_store.cpp

@@ -282,7 +282,7 @@ void Config_StoreSettings()  {
     EEPROM_WRITE_VAR(i, thermalManager.bedKd);
   #endif
 
-  #if DISABLED(HAS_LCD_CONTRAST)
+  #if !HAS_LCD_CONTRAST
     const int lcd_contrast = 32;
   #endif
   EEPROM_WRITE_VAR(i, lcd_contrast);
@@ -462,7 +462,7 @@ void Config_RetrieveSettings() {
       for (uint8_t q=3; q--;) EEPROM_READ_VAR(i, dummy); // bedKp, bedKi, bedKd
     #endif
 
-    #if DISABLED(HAS_LCD_CONTRAST)
+    #if !HAS_LCD_CONTRAST
       int lcd_contrast;
     #endif
     EEPROM_READ_VAR(i, lcd_contrast);
@@ -579,7 +579,7 @@ void Config_ResetDefault() {
     absPreheatFanSpeed = ABS_PREHEAT_FAN_SPEED;
   #endif
 
-  #if ENABLED(HAS_LCD_CONTRAST)
+  #if HAS_LCD_CONTRAST
     lcd_contrast = DEFAULT_LCD_CONTRAST;
   #endif
 
@@ -842,7 +842,7 @@ void Config_PrintSettings(bool forReplay) {
 
   #endif // PIDTEMP || PIDTEMPBED
 
-  #if ENABLED(HAS_LCD_CONTRAST)
+  #if HAS_LCD_CONTRAST
     CONFIG_ECHO_START;
     if (!forReplay) {
       SERIAL_ECHOLNPGM("LCD Contrast:");

Marlin/ultralcd.cpp

@@ -97,7 +97,7 @@ static void lcd_status_screen();
   static void lcd_control_motion_menu();
   static void lcd_control_volumetric_menu();
 
-  #if ENABLED(HAS_LCD_CONTRAST)
+  #if HAS_LCD_CONTRAST
     static void lcd_set_contrast();
   #endif
 
@@ -1352,7 +1352,7 @@ static void lcd_control_menu() {
   MENU_ITEM(submenu, MSG_MOTION, lcd_control_motion_menu);
   MENU_ITEM(submenu, MSG_VOLUMETRIC, lcd_control_volumetric_menu);
 
-  #if ENABLED(HAS_LCD_CONTRAST)
+  #if HAS_LCD_CONTRAST
     //MENU_ITEM_EDIT(int3, MSG_CONTRAST, &lcd_contrast, 0, 63);
     MENU_ITEM(submenu, MSG_CONTRAST, lcd_set_contrast);
   #endif
@@ -1712,7 +1712,7 @@ static void lcd_control_volumetric_menu() {
  * "Control" > "Contrast" submenu
  *
  */
-#if ENABLED(HAS_LCD_CONTRAST)
+#if HAS_LCD_CONTRAST
   static void lcd_set_contrast() {
     ENCODER_DIRECTION_NORMAL();
     if (encoderPosition) {
@@ -2383,7 +2383,7 @@ void lcd_setalertstatuspgm(const char* message) {
 
 void lcd_reset_alert_level() { lcd_status_message_level = 0; }
 
-#if ENABLED(HAS_LCD_CONTRAST)
+#if HAS_LCD_CONTRAST
   void lcd_setcontrast(uint8_t value) {
     lcd_contrast = value & 0x3F;
     u8g.setContrast(lcd_contrast);