use inttypes
diff --git a/src/lib9/fmt/plan9.h b/src/lib9/fmt/plan9.h
index 22fa7f0..0872ac7 100644
--- a/src/lib9/fmt/plan9.h
+++ b/src/lib9/fmt/plan9.h
@@ -1,4 +1,4 @@
-#include <stdint.h>
+#include <inttypes.h>
 
 /*
  * compiler directive on Plan 9