SDL_image: add guard to new IMG.h header.

SDL Commits
1 
From b1c92be885639771359c7bfed36aa30d30ce95f3 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Mon, 6 Mar 2023 14:01:24 +0300
Subject: [PATCH] add guard to new IMG.h header.

---
 IMG.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/IMG.h b/IMG.h
index c855d1e9..3106b8c4 100644
--- a/IMG.h
+++ b/IMG.h
@@ -19,6 +19,9 @@
   3. This notice may not be removed or altered from any source distribution.
 */
 
+#ifndef SDLIMAGE_IMG_H
+#define SDLIMAGE_IMG_H
+
 extern int IMG_InitAVIF(void);
 extern void IMG_QuitAVIF(void);
 extern int IMG_InitJPG(void);
@@ -32,3 +35,4 @@ extern void IMG_QuitTIF(void);
 extern int IMG_InitWEBP(void);
 extern void IMG_QuitWEBP(void);
 
+#endif