From db97a3550207486261d6b44d0e9771be36800d65 Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Fri, 16 Dec 2016 16:37:12 +0100
Subject: [PATCH] Check if atomic operations are supported

---
 configure.ac                | 11 +++++++++++
 src/libsodium/sodium/core.c |  2 +-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index b36a0877..90ff5413 100644
--- a/configure.ac
+++ b/configure.ac
@@ -660,6 +660,17 @@ AS_IF([test "x$aligned_access_required" = "xyes"],
   [AC_MSG_RESULT(no)
    AC_DEFINE([CPU_UNALIGNED_ACCESS], [1], [unaligned memory access is supported])])
 
+AC_MSG_CHECKING(if atomic operations are supported)
+AC_LINK_IFELSE([AC_LANG_PROGRAM([[ ]], [[
+static volatile int _sodium_lock;
+__sync_lock_test_and_set(&_sodium_lock, 1);
+__sync_lock_release(&_sodium_lock);
+]]
+)],
+[AC_MSG_RESULT(yes)
+ AC_DEFINE([HAVE_ATOMIC_OPS], [1], [atomic operations are supported])],
+[AC_MSG_RESULT(no)])
+
 dnl Checks for functions and headers
 
 AS_IF([test "x$EMSCRIPTEN" = "x"],[
diff --git a/src/libsodium/sodium/core.c b/src/libsodium/sodium/core.c
index aa23726e..1ac12cab 100644
--- a/src/libsodium/sodium/core.c
+++ b/src/libsodium/sodium/core.c
@@ -123,7 +123,7 @@ sodium_crit_leave(void)
     return 0;
 }
 
-#elif defined(__GNUC__) && !defined(__EMSCRIPTEN__) && !defined(__native_client__)
+#elif defined(HAVE_ATOMIC_OPS) && !defined(__EMSCRIPTEN__) && !defined(__native_client__)
 
 static volatile int _sodium_lock;