diff --git a/xf86atomic.h b/xf86atomic.h
index 2d733bd5..efa47a77 100644
--- a/xf86atomic.h
+++ b/xf86atomic.h
@@ -54,6 +54,7 @@ typedef struct {
 #endif
 
 #if HAVE_LIB_ATOMIC_OPS
+#define AO_REQUIRE_CAS
 #include <atomic_ops.h>
 
 #define HAS_ATOMIC_OPS 1