diff --git a/src/base/cl_maybe_inline.h b/src/base/cl_maybe_inline.h
index 4f7a982..9d185f4 100644
--- a/src/base/cl_maybe_inline.h
+++ b/src/base/cl_maybe_inline.h
@@ -102,7 +102,7 @@
  *    a function.
  * 2. It's ignored if the optimization is switched off.
  */
-#if defined(__GNUC__) && defined(CL_ATTRIBUTE_FLATTEN)
+#if defined(__GNUC__) && defined(CL_HAVE_ATTRIBUTE_FLATTEN)
 #define CL_FLATTEN __attribute__((flatten))
 #else
 #define CL_FLATTEN