Convert HMMIO to a void*.

diff --git a/include/mmsystem.h b/include/mmsystem.h
index a24eaab..0388452 100644
--- a/include/mmsystem.h
+++ b/include/mmsystem.h
@@ -40,7 +40,7 @@
 DECLARE_HANDLE(HMIDISTRM);
 DECLARE_HANDLE(HMIXER);
 DECLARE_HANDLE(HMIXEROBJ);
-DECLARE_OLD_HANDLE(HMMIO);
+DECLARE_HANDLE(HMMIO);
 
 #include "pshpack1.h"