Both of these functions, TTF_FontFaceStyleName() and
TTF_FontFaceFamilyName() return 'const char *'. Update variables to
match expected returned type.

Bug-Debian: http://bugs.debian.org/1015106

Taken from https://lists.gnu.org/archive/html/bug-freedink/2022-07/msg00001.html
--- a/src/gfx_fonts.cpp	1970-01-01 07:30:01.000000000 +0730
+++ b/src/gfx_fonts.cpp	2025-11-02 14:12:38.939879534 +0800
@@ -293,9 +293,9 @@
  */
 void setup_font(TTF_Font *font)
 {
-  char *familyname = TTF_FontFaceFamilyName(font);
+  const char *familyname = TTF_FontFaceFamilyName(font);
   if(familyname)
     log_info("The family name of the face in the font is: %s", familyname);
-  char *stylename = TTF_FontFaceStyleName(font);
+  const char *stylename = TTF_FontFaceStyleName(font);
   if(stylename)
     log_info("The name of the face in the font is: %s", stylename);
   log_info("The font max height is: %d", TTF_FontHeight(font));