diff --git a/src/os_win32.h b/src/os_win32.h
index 41a44bf..5303d6d 100644
--- a/src/os_win32.h
+++ b/src/os_win32.h
@@ -193,3 +193,17 @@
 #else
 # define vim_mkdir(x, y) mch_mkdir(x)
 #endif
+
+/* Enable common dialogs input unicode from IME if posible. */
+#ifdef FEAT_MBYTE
+    /* The variables are defined in os_win32.c. */
+extern LRESULT (WINAPI *pDispatchMessage)(LPMSG);
+extern BOOL (WINAPI *pGetMessage)(LPMSG, HWND, UINT, UINT);
+extern BOOL (WINAPI *pIsDialogMessage)(HWND, LPMSG);
+extern BOOL (WINAPI *pPeekMessage)(LPMSG, HWND, UINT, UINT, UINT);
+#else
+# define pDispatchMessage DispatchMessage
+# define pGetMessage GetMessage
+# define pIsDialogMessage IsDialogMessage
+# define pPeekMessage PeekMessage
+#endif