From 3f007af78283aea2e8c1a3addff7aeae862d8b28 Mon Sep 17 00:00:00 2001
From: Dave Airlie <airlied@redhat.com>
Date: Fri, 7 Nov 2025 13:14:56 +1000
Subject: [PATCH] c11/threads: fix build on c23

C23/glibc is now including once_init in stdlib.h

https://patchwork.sourceware.org/project/glibc/patch/78061085-f04a-0c45-107b-5a8a15521083@redhat.com/#213088

Just fix up our use of it.

Cc: mesa-stable
Reviewed-by: Yonggang Luo <luoyonggang@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38298>

Upstream-Status: Backport [v26.0.0 179e744f7577d98df7c79d7324c22acfb32a0154]
Signed-off-by: Martin Jansa <martin.jansa@gmail.com>
---
 src/c11/impl/threads_posix.c | 3 ++-
 src/c11/threads.h            | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/c11/impl/threads_posix.c b/src/c11/impl/threads_posix.c
index 2540e3e0c49..f75774fc51d 100644
--- a/src/c11/impl/threads_posix.c
+++ b/src/c11/impl/threads_posix.c
@@ -70,12 +70,13 @@ impl_thrd_routine(void *p)
 
 /*--------------- 7.25.2 Initialization functions ---------------*/
 // 7.25.2.1
+#ifndef __once_flag_defined
 void
 call_once(once_flag *flag, void (*func)(void))
 {
     pthread_once(flag, func);
 }
-
+#endif
 
 /*------------- 7.25.3 Condition variable functions -------------*/
 // 7.25.3.1
diff --git a/src/c11/threads.h b/src/c11/threads.h
index dbcb3459a9b..c849f385e30 100644
--- a/src/c11/threads.h
+++ b/src/c11/threads.h
@@ -118,8 +118,10 @@ typedef pthread_cond_t  cnd_t;
 typedef pthread_t       thrd_t;
 typedef pthread_key_t   tss_t;
 typedef pthread_mutex_t mtx_t;
+#ifndef __once_flag_defined
 typedef pthread_once_t  once_flag;
 #  define ONCE_FLAG_INIT PTHREAD_ONCE_INIT
+#endif
 #  ifdef PTHREAD_DESTRUCTOR_ITERATIONS
 #    define TSS_DTOR_ITERATIONS PTHREAD_DESTRUCTOR_ITERATIONS
 #  else
