SDL_image: Fixed build error when using SDL 2.0.22 or older

SDL Commits
1 
From 47344aad61a177317348233a451773d2c73fb571 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Sun, 19 Jun 2022 19:18:10 -0700
Subject: [PATCH] Fixed build error when using SDL 2.0.22 or older

---
 IMG_xcf.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/IMG_xcf.c b/IMG_xcf.c
index 14a35f02..d19b403d 100644
--- a/IMG_xcf.c
+++ b/IMG_xcf.c
@@ -26,6 +26,10 @@
 
 #ifdef LOAD_XCF
 
+#ifndef SDL_SIZE_MAX
+#define SDL_SIZE_MAX ((size_t)-1)
+#endif
+
 #if DEBUG
 static char prop_names [][30] = {
   "end",