libass: match font attachments based on extension

Sometimes fonts are muxed with the wrong MIME type, but we should
still be able to use them. Especially OpenType font collections are
affected by this. Match attachments by extensions .ttf, .otf and .ttc
in addition to MIME type to fix these issues.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/codec/libass.c

@@ -187,7 +187,21 @@ static int Create( vlc_object_t *p_this )
     {
         input_attachment_t *p_attach = pp_attachments[k];
 
+        bool found = false;
+
+        /* Check mimetype*/
         if( !strcasecmp( p_attach->psz_mime, "application/x-truetype-font" ) )
+            found = true;
+        /* Then extension */
+        else if( !found && strlen( p_attach->psz_name ) > 4 )
+        {
+            char *ext = p_attach->psz_name + strlen( p_attach->psz_name ) - 4;
+
+            if( !strcasecmp( ext, ".ttf" ) || !strcasecmp( ext, ".otf" ) || !strcasecmp( ext, ".ttc" ) )
+                found = true;
+        }
+
+        if( found )
         {
             msg_Dbg( p_dec, "adding embedded font %s", p_attach->psz_name );