Fix undefined max in multi-language (#15521)

Marlin/src/core/multi_language.h

@@ -65,7 +65,7 @@ typedef const char Language_Str[];
     lang == 3 ? GET_LANG(LCD_LANGUAGE_4)::MSG : \
                 GET_LANG(LCD_LANGUAGE_5)::MSG \
     )
-  #define MAX_LANG_CHARSIZE max(GET_LANG(LCD_LANGUAGE)::CHARSIZE, \
+  #define MAX_LANG_CHARSIZE _MAX(GET_LANG(LCD_LANGUAGE)::CHARSIZE, \
                                 GET_LANG(LCD_LANGUAGE_2)::CHARSIZE, \
                                 GET_LANG(LCD_LANGUAGE_3)::CHARSIZE, \
                                 GET_LANG(LCD_LANGUAGE_4)::CHARSIZE, \

Marlin/src/lcd/ultralcd.cpp

@@ -44,7 +44,7 @@
 #if HAS_SPI_LCD
   #if ENABLED(STATUS_MESSAGE_SCROLLING)
     uint8_t MarlinUI::status_scroll_offset; // = 0
-    constexpr uint8_t MAX_MESSAGE_LENGTH = max(LONG_FILENAME_LENGTH, MAX_LANG_CHARSIZE * 2 * (LCD_WIDTH));
+    constexpr uint8_t MAX_MESSAGE_LENGTH = _MAX(LONG_FILENAME_LENGTH, MAX_LANG_CHARSIZE * 2 * (LCD_WIDTH));
   #else
     constexpr uint8_t MAX_MESSAGE_LENGTH = MAX_LANG_CHARSIZE * (LCD_WIDTH);
   #endif