diff --git a/src/hnswbuild.c b/src/hnswbuild.c
index b15c144..ca82f77 100644
--- a/src/hnswbuild.c
+++ b/src/hnswbuild.c
@@ -36,6 +36,8 @@
  */
 #include "postgres.h"
 
+#include <limits.h>
+
 #include "access/genam.h"
 #include "access/parallel.h"
 #include "access/relscan.h"
diff --git a/src/hnswscan.c b/src/hnswscan.c
index ad8163c..32cdb7d 100644
--- a/src/hnswscan.c
+++ b/src/hnswscan.c
@@ -1,5 +1,7 @@
 #include "postgres.h"
 
+#include <limits.h>
+
 #include "access/genam.h"
 #include "access/relscan.h"
 #include "hnsw.h"