diff --git a/ext/digest/defs.h b/ext/digest/defs.h
index e7b90be023..bb55d984a2 100644
--- a/ext/digest/defs.h
+++ b/ext/digest/defs.h
@@ -18,7 +18,7 @@
 
 #if defined(HAVE_INTTYPES_H)
 # include <inttypes.h>
-#elif !defined __CYGWIN__
+#elif !defined __CYGWIN__ || !defined __INTTYPES_DEFINED__
   typedef unsigned char uint8_t;
   typedef unsigned int  uint32_t;
 # if SIZEOF_LONG == 8