SDL: stdinc: only use _Countof for SDL_arraysize when using a C standard > C23

SDL Commits
1 
From dd0536b1706f001c9c3b00b67f4a70e36ffba2c7 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Sat, 30 May 2026 02:25:16 +0200
Subject: [PATCH] stdinc: only use _Countof for SDL_arraysize when using a C
 standard > C23

---
 include/SDL3/SDL_stdinc.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/SDL3/SDL_stdinc.h b/include/SDL3/SDL_stdinc.h
index 3a7920abebc88..67347c9d4de33 100644
--- a/include/SDL3/SDL_stdinc.h
+++ b/include/SDL3/SDL_stdinc.h
@@ -256,7 +256,8 @@ void *alloca(size_t);
 #define SDL_arraysize(array) (sizeof(array)/sizeof(array[0]))  /* or `_Countof(array)` on recent gcc and clang */
 
 #else
-#if !defined(__cplusplus) && ((defined(__GNUC__) && __GNUC__ >= 16) || SDL_HAS_EXTENSION(c_countof))
+#if !defined(__cplusplus) && ((defined(__GNUC__) && __GNUC__ >= 16) || SDL_HAS_EXTENSION(c_countof)) \
+    && (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202500L)
 #define SDL_arraysize(array) _Countof(array)
 #else
 #define SDL_arraysize(array) (sizeof(array)/sizeof(array[0]))