SDL: fix preprocessor directive for SDL_RESTRICT definition in C99 case.

SDL Commits
1 
From 329b5f27d64ad40184957d308aeb88585cfc0b3a Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Fri, 30 May 2025 23:56:50 +0300
Subject: [PATCH] fix preprocessor directive for SDL_RESTRICT definition in C99
 case.

---
 include/SDL3/SDL_begin_code.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/SDL3/SDL_begin_code.h b/include/SDL3/SDL_begin_code.h
index 6628b49b91cda..e306a90652544 100644
--- a/include/SDL3/SDL_begin_code.h
+++ b/include/SDL3/SDL_begin_code.h
@@ -327,8 +327,8 @@
 
 /* `restrict` is from C99, but __restrict works with both Visual Studio and GCC. */
 #ifndef SDL_RESTRICT
-#  if defined(restrict) || ((defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901)))
-#    defined SDL_RESTRICT restrict
+#  if defined(restrict) || ((defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)))
+#    define SDL_RESTRICT restrict
 #  elif defined(_MSC_VER) || defined(__GNUC__) || defined(__clang__)
 #    define SDL_RESTRICT __restrict
 #  else