Codechange: nobody was using "str" parameter, so remove it

src/strings_func.h

@@ -277,7 +277,7 @@ public:
 	 */
 	virtual void SetFontNames(struct FreeTypeSettings *settings, const char *font_name, const void *os_data = nullptr) = 0;
 
-	bool FindMissingGlyphs(const char **str);
+	bool FindMissingGlyphs();
 };
 
 void CheckForMissingGlyphs(bool base_font = true, MissingGlyphSearcher *search = nullptr);