diff --git a/ar.c b/ar.c
index 596574e..550b2a1 100644
--- a/ar.c
+++ b/ar.c
@@ -23,6 +23,10 @@
  *
  */
 #include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <unistd.h>
 #include "busybox.h"
 
 typedef struct ar_headers_s {