From c63d6e516f406573e12775017822963aa8cda901 Mon Sep 17 00:00:00 2001
From: Love Hornquist Astrand <lha@h5l.org>
Date: Fri, 9 Sep 2011 10:03:28 +0200
Subject: [PATCH] use __sync_swap if we have it

---
 base/baselocl.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/base/baselocl.h b/base/baselocl.h
index 901e8606f..4eb6cb87a 100644
--- a/base/baselocl.h
+++ b/base/baselocl.h
@@ -68,7 +68,15 @@
 #define heim_base_atomic_type	unsigned int
 #define heim_base_atomic_max    UINT_MAX
 
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
+#if __has_builtin(__sync_swap)
+#define heim_base_exchange_pointer(t,v) __sync_swap((t), (v))
+#else
 #define heim_base_exchange_pointer(t,v) __sync_lock_test_and_set((t), (v))
+#endif
 
 #elif defined(_WIN32)