diff --git a/src/bitutils.h b/src/bitutils.h
index 0be6b71..bbebfd1 100644
--- a/src/bitutils.h
+++ b/src/bitutils.h
@@ -1,6 +1,12 @@
 #ifndef BITUTILS_H
 #define BITUTILS_H
 
+#include "postgres.h"
+
+#if PG_VERSION_NUM < 120000
+#error "Requires PostgreSQL 12+"
+#endif
+
 /* We use two types of dispatching: intrinsics and target_clones */
 /* TODO Move to better place */
 #ifndef DISABLE_DISPATCH
diff --git a/src/hnsw.h b/src/hnsw.h
index 7ec79ce..2f11137 100644
--- a/src/hnsw.h
+++ b/src/hnsw.h
@@ -12,10 +12,6 @@
 #include "utils/sampling.h"
 #include "vector.h"
 
-#if PG_VERSION_NUM < 120000
-#error "Requires PostgreSQL 12+"
-#endif
-
 #define HNSW_MAX_DIM 2000
 #define HNSW_MAX_NNZ 1000