SDL: Fix compilation error for Windows SDK 8.1+

SDL Commits
1 
From 3dbc4cf23348a901eab9d9b85687afa7e39690fd Mon Sep 17 00:00:00 2001
From: "Nicholas \"LB\" Braden" <[EMAIL REDACTED]>
Date: Tue, 30 Mar 2021 17:49:51 -0500
Subject: [PATCH] Fix compilation error for Windows SDK 8.1+

https://docs.microsoft.com/en-us/windows/win32/api/shellscalingapi/ne-shellscalingapi-monitor_dpi_type
---
 src/video/windows/SDL_windowsvideo.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/video/windows/SDL_windowsvideo.h b/src/video/windows/SDL_windowsvideo.h
index 86fbf3798..c7c4caaf2 100644
--- a/src/video/windows/SDL_windowsvideo.h
+++ b/src/video/windows/SDL_windowsvideo.h
@@ -85,6 +85,8 @@ typedef enum MONITOR_DPI_TYPE {
     MDT_DEFAULT = MDT_EFFECTIVE_DPI
 } MONITOR_DPI_TYPE;
 
+#else
+#include <shellscalingapi.h>
 #endif /* WINVER < 0x0603 */
 
 typedef BOOL  (*PFNSHFullScreen)(HWND, DWORD);