diff --git a/src/lib9/needstack.c b/src/lib9/needstack.c
new file mode 100644
index 00000000..b392d66b
--- /dev/null
+++ b/src/lib9/needstack.c
@@ -0,0 +1,8 @@
+#include <u.h>
+#include <libc.h>
+
+void
+needstack(int howmuch)
+{
+	USED(howmuch);
+}