dinput.h: define DIRECTINPUT_HEADER_VERSION as 0x0800 (bug #529)

(cherry picked from commit 38d327fd43032c672f08591bb944ce3b60dde45d)
diff --git a/mingw-w64-headers/direct-x/include/dinput.h b/mingw-w64-headers/direct-x/include/dinput.h
index b575480..14438f7 100644
--- a/mingw-w64-headers/direct-x/include/dinput.h
+++ b/mingw-w64-headers/direct-x/include/dinput.h
@@ -23,6 +23,7 @@
 #include <objbase.h>
 #include <_mingw_dxhelper.h>
 
+#define DIRECTINPUT_HEADER_VERSION	0x0800
 #ifndef DIRECTINPUT_VERSION
 #define DIRECTINPUT_VERSION	0x0800
 #endif