builtin-rev-list.c: mark file-local function static

Signed-off-by: Junio C Hamano <gitster@pobox.com>

bisect.h

@@ -27,8 +27,6 @@ struct rev_list_info {
 	const char *header_prefix;
 };
 
-extern int show_bisect_vars(struct rev_list_info *info, int reaches, int all);
-
 extern int bisect_next_all(const char *prefix);
 
 extern int estimate_bisect_steps(int all);

builtin-rev-list.c

@@ -253,7 +253,7 @@ static void print_var_int(const char *var, int val)
 	printf("%s=%d\n", var, val);
 }
 
-int show_bisect_vars(struct rev_list_info *info, int reaches, int all)
+static int show_bisect_vars(struct rev_list_info *info, int reaches, int all)
 {
 	int cnt, flags = info->bisect_show_flags;
 	char hex[41] = "";