diff --git a/src/base/abci/abcFx.c b/src/base/abci/abcFx.c
index 81b3e8028..60461a4a5 100644
--- a/src/base/abci/abcFx.c
+++ b/src/base/abci/abcFx.c
@@ -22,6 +22,7 @@
 #include "misc/vec/vecWec.h"
 #include "misc/vec/vecQue.h"
 #include "misc/vec/vecHsh.h"
+#include "opt/fxch/Fxch.h"
 
 ABC_NAMESPACE_IMPL_START