diff --git a/builtin/env--helper.c b/builtin/env--helper.c
index 1083c0f707..23c214fff6 100644
--- a/builtin/env--helper.c
+++ b/builtin/env--helper.c
@@ -7,7 +7,7 @@ static char const * const env__helper_usage[] = {
 	NULL
 };
 
-enum {
+static enum {
 	ENV_HELPER_TYPE_BOOL = 1,
 	ENV_HELPER_TYPE_ULONG
 } cmdmode = 0;