Configure: fixed test of OS X atomic(3).

auto/os/darwin

diff --git a/auto/os/darwin b/auto/os/darwin
index 590e036..b97518a 100644
--- a/auto/os/darwin
+++ b/auto/os/darwin
@@ -112,5 +112,5 @@
 ngx_feature_path=
 ngx_feature_libs=
 ngx_feature_test="int32_t  lock, n;
-                  n = OSAtomicCompareAndSwap32Barrier(0, 1, lock)"
+                  n = OSAtomicCompareAndSwap32Barrier(0, 1, &lock)"
 . auto/feature