diff --git a/src/hb-atomic.hh b/src/hb-atomic.hh
index e92ccbca1..8b4ecb8fc 100644
--- a/src/hb-atomic.hh
+++ b/src/hb-atomic.hh
@@ -50,7 +50,7 @@
 /* Defined externally, i.e. in config.h. */
 
 
-#elif !defined(HB_NO_MT) && defined(__ATOMIC_ACQUIRE)
+#elif !defined(HB_NO_MT) && defined(__ATOMIC_ACQUIRE) && 0
 
 /* C++11-style GCC primitives. We prefer these as they don't require linking to libstdc++ / libc++. */