patch 8.2.0248: MS-Windows: dealing with deprecation is too complicated

Problem:    MS-Windows: dealing with deprecation is too complicated.
Solution:   Use io.h directly. Move _CRT_SECURE_NO_DEPRECATE to the build
            file. Suppress C4091 warning by setting "_WIN32_WINNT". (Ken
            Takata, closes #5626)
diff --git a/src/vim.h b/src/vim.h
index ca0f6b1..62cc46c 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -18,7 +18,7 @@
 #endif
 
 #ifdef MSWIN
-# include "vimio.h"
+# include <io.h>
 #endif
 
 // ============ the header file puzzle: order matters =========