butano: add config `BN_CFG_SPRITE_TEXT_MAX_UTF8_CHARACTERS_FOR_DUPLIC…

…ATION_CHECK` to save compile time when building fonts with big charaset

Current implementation of _duplicated_utf8_characters() is inefficient
with time complexity of O(N^2). Project build process will hang for an untolerable long time when many characters exist.The duplication check for fonts with big
charaset can be done in font making or converting phase. It is
unnecessary to do it in assertion.

butano/include/bn_config_sprite_text.h

@@ -26,4 +26,15 @@
     #define BN_CFG_SPRITE_TEXT_MAX_UTF8_CHARACTERS 4096
 #endif
 
+/**
+ * @def BN_CFG_SPRITE_TEXT_MAX_UTF8_CHARACTERS_FOR_DUPLICATION_CHECK
+ *
+ * Specifies the maximum number of UTF-8 characters for duplication check to save compile time.
+ *
+ * @ingroup text
+ */
+#ifndef BN_CFG_SPRITE_TEXT_MAX_UTF8_CHARACTERS_FOR_DUPLICATION_CHECK
+    #define BN_CFG_SPRITE_TEXT_MAX_UTF8_CHARACTERS_FOR_DUPLICATION_CHECK 100
+#endif
+
 #endif

butano/include/bn_sprite_font.h

@@ -118,7 +118,8 @@ class sprite_font
         BN_ASSERT(utf8_characters_ref.size() <= BN_CFG_SPRITE_TEXT_MAX_UTF8_CHARACTERS,
                    "Invalid UTF-8 characters count: ", utf8_characters_ref.size());
         BN_ASSERT(_validate_utf8_characters(), "UTF-8 characters validation failed");
-        //BN_ASSERT(! _duplicated_utf8_characters(), "There's duplicated UTF-8 characters");
+        BN_ASSERT(BN_CFG_SPRITE_TEXT_MAX_UTF8_CHARACTERS > BN_CFG_SPRITE_TEXT_MAX_UTF8_CHARACTERS_FOR_DUPLICATION_CHECK ||
+                   ! _duplicated_utf8_characters(), "There's duplicated UTF-8 characters");
         BN_ASSERT(character_widths_ref.empty() ||
                    character_widths_ref.size() == 1 + minimum_graphics + utf8_characters_ref.size(),
                    "Invalid character widths count: ", character_widths_ref.size(), " - ",