Don't delete testdir after running test.sh. Add it to make clean instead.
diff --git a/Makefile b/Makefile
index 01f6a21..a35d9a2 100644
--- a/Makefile
+++ b/Makefile
@@ -32,8 +32,8 @@
@for i in `./instlist`; do ln -s toybox "$(PREFIX)/$$i"; done
clean::
- rm -f toybox toybox_unstripped generated/config.h generated/Config.in \
- generated/newtoys.h generated/globals.h instlist
+ rm -rf toybox toybox_unstripped generated/config.h generated/Config.in \
+ generated/newtoys.h generated/globals.h instlist testdir
distclean: clean
rm -f toybox_old .config* generated/help.h