Index: lily/include/open-type-font.hh
--- lily/include/open-type-font.hh.orig
+++ lily/include/open-type-font.hh
@@ -26,8 +26,8 @@
 #include <utility>
 
 Index_to_charcode_map make_index_to_charcode_map (FT_Face face);
-void get_unicode_name (char *s, FT_ULong code);
-void get_glyph_index_name (char *s, FT_ULong code);
+void get_unicode_name (char *s, size_t size, FT_ULong code);
+void get_glyph_index_name (char *s, size_t size, FT_ULong code);
 
 struct Preinit_Open_type_font
 {
