Define SNDMSG.

include/commdlg.h

diff --git a/include/commdlg.h b/include/commdlg.h
index cb19da0..7bd144f 100644
--- a/include/commdlg.h
+++ b/include/commdlg.h
@@ -28,6 +28,14 @@
 #include "prsht.h"
 #include "pshpack1.h"
 
+#ifndef SNDMSG
+#ifdef __cplusplus
+#define SNDMSG ::SendMessage
+#else   /* __cplusplus */
+#define SNDMSG SendMessage
+#endif  /* __cplusplus */
+#endif  /* SNDMSG */
+
 #define OFN_READONLY                 0x00000001
 #define OFN_OVERWRITEPROMPT          0x00000002
 #define OFN_HIDEREADONLY             0x00000004