diff --git a/include/align.hpp b/include/align.hpp
index 2f9a33db..8ce50bb2 100644
--- a/include/align.hpp
+++ b/include/align.hpp
@@ -5,6 +5,7 @@
 
 #include <cstdlib>
 
+#include "compiler_builtins.hpp"
 #include "helpers.hpp"
 
 #ifdef _WIN32