diff --git a/src/cmd/mk/sys.h b/src/cmd/mk/sys.h
new file mode 100644
index 00000000..f520b066
--- /dev/null
+++ b/src/cmd/mk/sys.h
@@ -0,0 +1,4 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <regexp.h>