Don’t assume that each tagging format is only used by one file format

lib/libtags/tags.c

@@ -71,7 +71,9 @@ tagsget(Tagctx *ctx)
 	for(i = 0; i < nelem(g); i++){
 		ctx->num = 0;
 		if(g[i].f(ctx) == 0){
+			if(ctx->format == Funknown){
 				ctx->format = g[i].format;
+			}
 			res = 0;
 		}
 		ctx->seek(ctx, ctx->restart, 0);