diff --git a/XI2proto.h b/XI2proto.h
index 2fd91eb..84574a5 100644
--- a/XI2proto.h
+++ b/XI2proto.h
@@ -60,6 +60,7 @@
 #include <X11/Xproto.h>
 #include <X11/X.h>
 #include <X11/extensions/XI2.h>
+#include <stdint.h>
 
 /* make sure types have right sizes for protocol structures. */
 #define Window  uint32_t