SDL: Fixed error: variable 'nfences' set but not used

From 8b0798a3da7dbd98c28c89fedf9eea62f11b7661 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Mon, 2 Sep 2024 08:09:25 -0700
Subject: [PATCH] Fixed error: variable 'nfences' set but not used

---
 src/stdlib/SDL_malloc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/stdlib/SDL_malloc.c b/src/stdlib/SDL_malloc.c
index ad2f769ac9353..6d174057dfa19 100644
--- a/src/stdlib/SDL_malloc.c
+++ b/src/stdlib/SDL_malloc.c
@@ -4046,6 +4046,7 @@ static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) {
     else
       break;
   }
+  (void)nfences;
   assert(nfences >= 2);
 
   /* Insert the rest of old top into a bin as an ordinary free chunk */