From 4333e2ddcb5c5e0927c630bc5c17bdf915a71696 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 15 Apr 2026 02:37:41 +0300
Subject: [PATCH] compress.zstd: fix test failure under clang20 on alpine
 (fixes #24711)

---
 thirdparty/zstd/zstd.c       |  4 ++--
 thirdparty/zstd/zstd_v.patch | 21 +++++++++++++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/thirdparty/zstd/zstd.c b/thirdparty/zstd/zstd.c
index a234293c5..a8df59922 100644
--- a/thirdparty/zstd/zstd.c
+++ b/thirdparty/zstd/zstd.c
@@ -47390,7 +47390,7 @@ static int COVER_cmp8(COVER_ctx_t *ctx, const void *lp, const void *rp) {
  */
 #if (defined(_WIN32) && defined(_MSC_VER)) || defined(__APPLE__)
 static int WIN_CDECL COVER_strict_cmp(void* g_coverCtx, const void* lp, const void* rp) {
-#elif defined(_GNU_SOURCE)
+#elif defined(_GNU_SOURCE) && !defined(ZSTD_USE_C90_QSORT)
 static int COVER_strict_cmp(const void *lp, const void *rp, void *g_coverCtx) {
 #else /* C90 fallback.*/
 static int COVER_strict_cmp(const void *lp, const void *rp) {
@@ -47406,7 +47406,7 @@ static int COVER_strict_cmp(const void *lp, const void *rp) {
  */
 #if (defined(_WIN32) && defined(_MSC_VER)) || defined(__APPLE__)
 static int WIN_CDECL COVER_strict_cmp8(void* g_coverCtx, const void* lp, const void* rp) {
-#elif defined(_GNU_SOURCE)
+#elif defined(_GNU_SOURCE) && !defined(ZSTD_USE_C90_QSORT)
 static int COVER_strict_cmp8(const void *lp, const void *rp, void *g_coverCtx) {
 #else /* C90 fallback.*/
 static int COVER_strict_cmp8(const void *lp, const void *rp) {
diff --git a/thirdparty/zstd/zstd_v.patch b/thirdparty/zstd/zstd_v.patch
index 8d606e372..d6197ec02 100644
--- a/thirdparty/zstd/zstd_v.patch
+++ b/thirdparty/zstd/zstd_v.patch
@@ -76,6 +76,27 @@
  static COVER_ctx_t *g_coverCtx = NULL;
  #endif
  
+@@ -47390,7 +47412,7 @@ static int COVER_cmp8(COVER_ctx_t *ctx, const void *lp, const void *rp) {
+  * Same as COVER_cmp() except ties are broken by pointer value
+  */
+ #if (defined(_WIN32) && defined(_MSC_VER)) || defined(__APPLE__)
+ static int WIN_CDECL COVER_strict_cmp(void* g_coverCtx, const void* lp, const void* rp) {
+-#elif defined(_GNU_SOURCE)
++#elif defined(_GNU_SOURCE) && !defined(ZSTD_USE_C90_QSORT)
+ static int COVER_strict_cmp(const void *lp, const void *rp, void *g_coverCtx) {
+ #else /* C90 fallback.*/
+ static int COVER_strict_cmp(const void *lp, const void *rp) {
+@@ -47406,7 +47428,7 @@ static int COVER_strict_cmp(const void *lp, const void *rp) {
+  * Faster version for d <= 8.
+  */
+ #if (defined(_WIN32) && defined(_MSC_VER)) || defined(__APPLE__)
+ static int WIN_CDECL COVER_strict_cmp8(void* g_coverCtx, const void* lp, const void* rp) {
+-#elif defined(_GNU_SOURCE)
++#elif defined(_GNU_SOURCE) && !defined(ZSTD_USE_C90_QSORT)
+ static int COVER_strict_cmp8(const void *lp, const void *rp, void *g_coverCtx) {
+ #else /* C90 fallback.*/
+ static int COVER_strict_cmp8(const void *lp, const void *rp) {
+ 
 @@ -47405,7 +47427,7 @@
      qsort_r(ctx->suffix, ctx->suffixSize, sizeof(U32),
              ctx,
-- 
2.39.5