ziptool turn on zstd
diff --git a/src/ziptool.c b/src/ziptool.c
index cdcecc7..0c28bde 100644
--- a/src/ziptool.c
+++ b/src/ziptool.c
@@ -653,6 +653,11 @@
       return ZIP_CM_XZ;
 
 #endif
+#if defined(HAVE_LIBZSTD)
+    else if (strcasecmp(arg, "zstd") == 0)
+      return ZIP_CM_ZSTD;
+
+#endif
     else if (strcasecmp(arg, "unknown") == 0)
 	return 100;
     return 0; /* TODO: error handling */