diff --git a/help.c b/help.c
index 812af4cdea..8393c25586 100644
--- a/help.c
+++ b/help.c
@@ -540,7 +540,8 @@ static struct cmdnames aliases;
 #define AUTOCORRECT_NEVER (-2)
 #define AUTOCORRECT_IMMEDIATELY (-1)
 
-static int git_unknown_cmd_config(const char *var, const char *value, void *cb)
+static int git_unknown_cmd_config(const char *var, const char *value,
+				  void *cb UNUSED)
 {
 	const char *p;