diff --git a/make.sh b/make.sh
index 856b6da..44562be 100755
--- a/make.sh
+++ b/make.sh
@@ -129,3 +129,6 @@ if [ "$1" = "clean" ]; then
   /bin/rm -f Makefile _os_define.h
 fi
 
+if [ "$1" = "clean" ]; then
+  /bin/rm -f Makefile _os_bits.h
+fi