diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index b956d2a5d3..a283fcb33a 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -17,6 +17,7 @@
 #include <ctype.h>
 #include <unistd.h>
 #include <sys/stat.h>
+#include <sys/wait.h>
 
 #include "access/heapam.h"
 #include "access/htup_details.h"