add exitcode
diff --git a/src/lib9/exitcode.c b/src/lib9/exitcode.c
new file mode 100644
index 0000000..f65836e
--- /dev/null
+++ b/src/lib9/exitcode.c
@@ -0,0 +1,9 @@
+#include <u.h>
+#include <libc.h>
+
+int
+exitcode(char *s)
+{
+	return 1;
+}
+