diff --git a/remote.c b/remote.c
index 5b9c6931c1e..0b3939ce814 100644
--- a/remote.c
+++ b/remote.c
@@ -2156,7 +2156,7 @@ struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fet
 /*
  * Compare-and-swap
  */
-void clear_cas_option(struct push_cas_option *cas)
+static void clear_cas_option(struct push_cas_option *cas)
 {
 	int i;
 
diff --git a/remote.h b/remote.h
index 8b62efd2adc..31ccdcd14f4 100644
--- a/remote.h
+++ b/remote.h
@@ -260,7 +260,6 @@ struct push_cas_option {
 
 extern int parseopt_push_cas_option(const struct option *, const char *arg, int unset);
 extern int parse_push_cas_option(struct push_cas_option *, const char *arg, int unset);
-extern void clear_cas_option(struct push_cas_option *);
 
 extern int is_empty_cas(const struct push_cas_option *);
 void apply_push_cas(struct push_cas_option *, struct remote *, struct ref *);