libass: Set Arial as the default family.

This is a fallback option in case we cannot find a match. We don't set a default actual font, since we do not ship one with VLC. We can set one per platform, but I don't think it is worth the trouble.

modules/codec/libass.c

@@ -719,8 +719,8 @@ static ass_handle_t *AssHandleYield( decoder_t *p_dec )
     ass_set_font_scale( p_renderer, 1.0 );
     ass_set_line_spacing( p_renderer, 0.0 );
 
-    const char *psz_font = "";//"/usr/src/videolan/vlc-libass.git/share/skins2/fonts/FreeSans.ttf"; // FIXME
-    const char *psz_family = "";//"Arial"; // FIXME
+    const char *psz_font = NULL; /* We don't ship a default font with VLC */
+    const char *psz_family = "Arial"; /* Use Arial if we can't find anything more suitable */
 #ifdef HAVE_FONTCONFIG
     ass_set_fonts( p_renderer, psz_font, psz_family );  // setup default font/family
 #else