usage.c: remove reference to busybox.h
*: s/include "busybox.h"/include "libbb.h"

diff --git a/util-linux/hexdump.c b/util-linux/hexdump.c
index 85a4490..36ed1e9 100644
--- a/util-linux/hexdump.c
+++ b/util-linux/hexdump.c
@@ -10,7 +10,7 @@
  */
 
 #include <getopt.h>
-#include "busybox.h"
+#include "libbb.h"
 #include "dump.h"
 
 /* This is a NOEXEC applet. Be very careful! */